A mage in SR4 who astrally projects can invisibly and invulnerably scout their target. If the target doesn't have magical defenses, this can give huge advantages; when infliltrating a guarded facility, it helps to have already located all the guard posts and studied the patrol schedule. I can see a character taking Magician just for this ability, leaving Magic at 1, and otherwise putting all their BP into scout and covert entry skills! (and maybe learning Spellcasting (Illusions) and Invisibility; even at Force 1, it's a bonus.) Also using Watcher Spirits for similar purposes, and possibly having them materialize to distract guards.

Anyways, even a high-Magic mage can't astrally scout and carpet-bomb from the astral onto targets on the physical, who would have little way to defend themselves or respond or even flee effectively. Here's what to do for high impact and low risk: A Mage can summon a Spirit, buff it, send it to the scouted location, and have it materialize and attack. Is this as nasty a tactic as I imagine? An F5 spirit already has Immunity to any weapon of DV 10 or less. If the mage casts Combat Sense on it, then it'll have +5 dice to avoid attacks, so it'll be hard to get net hits for extra DV, and if the mage also casts Armor, it might survive a DV 11+ attack anyways. F5 Earth Spirit buffed thusly is REA 7, with F5 Combat Sense rolling 12 dice to avoid attacks, and BOD 9, with F5 Armor rolling 14 dice to soak damage. Meanwhile, if it grabs for Subdual Combat, once it hits, target will have arms pinned unless they can beat a STR+Unarmed Combat test vs the spirit's DP of 14, and target takes 9S automatically every following IP. The spirit only has 8 dice to hit, but as no one can hurt it, it can just keep trying, and once it hits, the fight's over for anyone but a super-strong martial artist, or someone who can fight without moving their arms, or someone who can soak 9S indefinitely.

Meanwhile, the mage is sustaining two spells and at -4 to all actions, but if she has a decent hiding spot (and maybe Invisibility), she can be reading a book or playing solitaire while the spirit does all the fighting. If the spirit fails, then she just summons another one. If she's merciful to her spirits, she summons one and it fights until it takes a few boxes of damage, then she dismisses it and has another spirit take a turn.

Alternatively, what if a mage buffs their three teammates and a spirit with those spells, and afterwards is sustaining four of each spell... she's at -8 to all actions, so she hides until the fight's over. (The player runs the spirit in combat, so they are declaring actions and rolling dice just like any other player.) Granted, she may have a hard time getting full hits on those last few castings. At MAG 5 and Spellcasting 5, she starts with 10 dice and end with 2. Unless she also has Specialization and/or Focus and/or a relevant Mentor bonus and/or taps a bound spirit for spellcasting assistance, in which case it just takes a few more tries at 3 seconds each; maybe the last few buffs are cast at F3.

These tactics do require lots of Drain resistance, but they can be done without overcasting, and other threads have included some Drain-resistant builds, eg hermetic dwarf with 6 WIL and 5( LOG, or elf shaman with 5 WIL and 7 CHA.

One other tactic: if mage knows the Heal spell, summon a Spirit of Man with the Heal spell, and request "continual use of a power". Fortunately for balance, making a Heal's effect permanent takes two Turns per box of damage, so once someone on the mage's team takes a hit, the spirit spends the rest of the fight sustaining its Heal; it's still nice to know that your first wound will be instahealed, up to 3 boxes or so with an F5 spirit (DP 10 for spellcasting).

All good stuff, but a few suggestions: the astral scout/carpet-bomber paragraph assumes that the mage is operating without opposition against a completely non-magical target. In Shadowrun anything worth breaking into has magical security such as wards, watchers, guard spirits, and AP weapons. You'll especially need to worry about wards because they are cheap and are tough for an astral character and spirit to get into.

Buffs are great, but who wants to buff their friends then go and hide the rest of the game? Having said that, you can buff your friends and still play the game yourself if you use something else to sustain your spells for you. (Also don't forget to check out the errata, sustaining spells do not affect your spellcasting dice.) According to the RAW, ally spirits are best for sustaining spells because a force 1 ally can sustain infinite spells with no penalty or spell force limitations (but check if your GM nerfed that). The main downside with sustaining spells is that every time you want to enter a ward, you'll have to terminate all your spells and recast them inside the ward or you set off the alarm. This makes it tough to keep high force spells running all the time because you get hit with multiple high drain spells every time you want to go into a ward.

Hope this helps, happy hunting.

I think you have defined the core of a good supporting mage.

Real builds should have medium magic, and use any saved points on buying more skills. They should have a few sustaining foci running, that does offer more than having high magic attribute. Health, Illusion, Manipulation all have very useful spells to sustain.

...and/or that someone like Dr Z (#87) with his EXEX loaded PJSS isn't lurking around the place.

I'm not really that big of a fan of mage buffs. They're OK, and can accomplish a lot in the right circumstances, but my problem was and remains the idea that they push more versatile spells or immediately effective spells out of the list. And actually, the level of micromanagement a player has over a Spirit in combat without burning services is rather open to interpretation. Continual use of powers in combat counts as one service, but it never says anything about how fine a degree of control it is, so whether the player gets to "play the spirit" or can give the spirit some prime directives to act upon in good faith is basically up to the GM.

I just want to make clear that the rating of Immunity to Normal Weapons is compared to the modified DV of the weapon, which is base DV + net hits.

By the way...

buff the spirit with what, exactly?

Most "buff" spells are physical, and thus not castable on the astral. Those that aren't (such as basic invisibility) leave open the question of whether or not the spell's effect can cross the physical/astral divide (most sane GMs would rule no.)

Ah yes, that I'll agree on. I ment for buffing the team and possibly a spirit before sending them all into a building.

Immunity to normal weapons is base DV plus hits? Huh, I though it was just the weapons base DV. What happens when the gun totting fool does a long burst? Are the extra die ignored when figuring out immunity?

bonus DV from burst fire does not count towards penetrating armor, including a spirit's immunity to normal weapons.

which is why you use a wide burst, which will reduce their dice pool for dodging, which gives you more net hits, which increases your DV, which makes it more likely to penetrate armor (including a spirit's immunity to normal weapons)