That would be major overkill.

All you need is 4+ street samurai with Ingram Valiants w/ gyroharnesses and loaded with EX-EX ammo.

Let's say they have Heavy Weapons 4, Agility 6, and smartlinks. They'll call their shots for +4 DV. That's 8 dice, for 2.6 (repeating) hits.

Great Dragons have Reaction 11. So, fire 2 wide full bursts. You have enough recoil comp to compensate for all of that. Lofwyr spends all of his Edge using his twist fate power to make 3 of the street samurai to reroll their hits, making their attacks ineffective. He takes the last two bursts, and he doesn't roll any dice to dodge (11-5 (wide burst)- 6(previous attacks)=0). So, he soaks 14.6 (repeating) P damage with 25 Body dice+ 10 Armor dice. He'll score 11.6 (repeating) hits, taking 3 Physical Damage from each.

Lofwyr fills in his Physical Track with 6 boxes of damage. He has 14 boxes remaining. Now its Lofwyr's turn. He decides to fry one with his fire breath, because they were smart and spread out to prevent them all being nuked by a single fireball.

So, Lofwyr breaths fire at one, rolling 14 dice on the Exotic Ranged Weapon test, for 4.6 (repeating) successes. The street sam tries to dodge (let's say he has 9 Reaction). So, the poor street sam takes 13P damage, and is probably unconscious and dieing.

So, the other three street sams continue firing at Lofwyr. They all call their shots at +4 DV. They roll their 8 dice, scoring 2.6 (repeating) hits. Lofwyr rolls 11-5-2=4 dice to dodge with against the first attack, scoring 1.3 (repeating) hits. He then soaks 13.3 (repeating) P damage with 25 Body + 10 Armor, scoring 11.6 (repeating) hits, taking 1 box of damage. 13 boxes left.

Lofwyr rolls three dice to dodge the second shot. The .3 fewer hits he scores results in him taking 2 boxes of damage this time. 11 boxes left.

Lofwyr rolls a single die to dodge the third attack (11- 5- 3- 2=1), scoring a mere .3 (repeating) hits. He scores 11.3 successes on the damage resistance test, taking 3 damage. 8 boxes left.

The last three attacks are exactly the same as the first two damaging ones. Lofwyr takes 3P damage from each, sending him into Overdamage. He'll take another box of damage every 1 minute, 15 seconds: He has roughly half an hour for SK medics to show up and save him, unless the sams do something about it. He can't dodge, so if one of them can see where his body fell, it would be easy enough to open up with narrow wide bursts, each of which will deal 9 damage to Lofwyr. It would take 3 of them to finish of Lofwyr off, and then it's time to run like hell and and be as surprised as anything when the executors of Lofwyr's estate give everything he has to them (because old Lofwyr's something of a traditionalist- the people responsable for killing the dragon get his hoard, by dragon traditions, though the other Greats will probably make lucrative offers to get their scaly claws on his memory crystals, which metahumans can't use anyway).

Net result: -1 Street Samurai, -1 Great Dragon. The surviving sams gain control of a megacorp.

A note on the result: This is actually much closer than the equivalent matchups in SR3. It's a sad, sad day when a dragon's best shot at survival is turning itself invisible and running, though.

Well, that depends on how you've read the "+10/12" entry in the old editions.
One may read it as +10 Body, 12 Armor, or (as i always did) +10 Body, +12 Armor. So in my campaigns GDs always had 20 hardened armor. And the new edition confirmes that for me. But YMMV of course.