Too make up for my previous out burst:
I had a petro Voudoo hugan of baron Samedi Sons of Sauron terrorist enter a spirit pact with a master shedim. They entered hospital morgues via magic. Killed everyone in the morgue. Breach the wards on the morgue for shedim to enter the bodies.
Master shedim and hougan team up and kill investigating astral projecting mage/shaman.
Then the master shedim in the body of a former decker sealed all the doors and silenced all the alarms via the matrix. Set a delay of 48 hours on the doors to unlock. Release shedim and zombie hoard.
Move to next population center along the mana line, repeat. The idea was to taint the entire mana line with death and pain. While getting more powerful shedim/potency/terror from humans

Hey, one of the Roman Catholic Church's fastest-growing areas is Africa. And, well... age is more relative there.

You could replace Catholic with Fundamentalist Mormon if you had about a dozen female accomplices to pose as your other wives.

The way the potency rules work never set well with me. "Completion of Great Work of Evil 'A' increases Stat 'B'!"
Yay. It's a quick-and-easy way to scale a villain in response to in-game events, so it's not all bad for overworked GMs (That would be most of us.)

I prefer, though, to have these plans result in more specific gains. Such as initiation, the creation of powerful foci, access to powers that would be unavailable normally. straight stat-boosts or more subtle rewards, such as a measure of power over those falling under the influence of your works.

Here is a random idea.
Firewire
The Plan
Seattle's power-grid has been undergoing a number of major upgrades and repairs lately. Not the least of which being the replacement of a LOT of power-lines and sub-stations in and around the city.
Westinghouse, a mage who was once an electrical engineer, has been using a combination of blackmail, low-level shadow-ops, and extortion to make certain changes to these plans.
Cables bound for these projects have been doped with his alchemical radicals, and the occasional ritual.
Buried deep within circuits that will soon be routing power to homes and bussinesses all across the metroplex are strange circuits that don't seem to do anything, but look strange.
Once these elements are in place Westinghouse must ritualy electrocute a human sacrifice at a power substation to "activate" it.
The Payoff

• Bonus dice to electrical elemental spells when within LOS of one of his magicaly doped wires, equal to the number of activated power-stations that wire can "connect" too. (Thus the GM can scale the power when and how he wishes, and Westinghouse has a valid reason to perform the ritual as often as he can)
• Access to the regeneration critter-power by way of ritualy electrocuting himself with power from his doped wires. (If they connect to an active station.)
• When astrally projecting near one of his wires he may cast a lightening-based spell at physical targets without penalty, but doing so blows out power to the neighborhood, so he only get's one shot.

Heart-strings

The Plan
Even in the 2060's people aren't taking proper care of cardiovascular system, and occasionally they even need to have their ticker replaced. So, your original heart, once the seat of your emotions that literally pumped life itself through your veins; what happens to it once it has been cast aside like a broken tool?
Dyre, a shaman with a penchant for controlling people, believes it could become a powerful weapon to hold over it's former owner.
The plan is this.
1> Obtain a cybernetic rabbit heart (preferably more than one) and the knowledge of it's installation (or outsource it) to begin experiments in using the original heart as a powerful material link focus. (We can keep a rabbit's heart alive outside the body for some time, IRL.) Eventually move on to human subjects.
2> Identify and obtain technologies and/or magics that will allow a human heart to survive indefinitely (or darn near it) outside the body.
3> Identify powerful individuals who are likely to need a heart-transplant within the next 5 years and monitor them. Perhaps help them along with certain poisons or ritual sendings.
4>When one of the targets eventually goes in for surgery, hire shadowrunners to obtain the original heart ASAP, as there is only a window of a few hours wherein it will remain viable.
5> ?
6> Profit!

The Payoff
This plan will take a few years to reach fruition, but the rewards could be great.
He will have created a Living Link Focus; a magical tool that greatly aids all ritual magics used against it's target. It: adds dice equal to the target's essence to the force of any spell cast through it, allows the casting magician to ignore the "Poor link" edge and reduces the effective force of any wards protecting the target by 1/2. You can assense the target, through the Focus, as if it were still part of him. Squeezing the focus acts as an "agonizing pain" spell on the target. Destroying it improperly (IE: Shotgun blasts) will cast a Death spell on the target with a force equal to his essence; if he resists he no longer has to worry about it, if he fails he has a massive heart-attack and shuffles off the mortal coil.
Needless to say, once he's finished creating this new focus, his "How I did it" lecture-notes will be worth millions.

Getting Involved

• Cybernetic parts for critters don't come cheap (An IRL heart lung machine on Ebay can be had for about $2500, that's kind of creepy really). For that price a team of reasonably competent scum could snag all the cyber-hearts they can carry, an autoclave AND a couple other odds and ends from a high-end veterinary clinic! Thus your team is hired, and charged with the task of ripping off Dr. Doolittle.
• The equipment to keep human organs alive for extended periods is likewise outrageously priced, and experimental! (I think current techniques boil down to "Keep it on ice, don't let it dry out, don't brake for yellow lights.") The team is hired and charged with the task of ripping of Pacific Medical Preservatives, who are on the verge of bringing just what Dyre needs to the market.
• Break into 3 area hospitals and clinics and obtain the medical records for everyone on this list.
• Insert this poison into Mr Iyabochi's coffee-cup, sitting on his desk in The Office Building That Eats Shadowrunners. If they do well, he has a list of 3 more people he wants poisoned in this fashion. (The poison is actually a chemical that greatly enhances the buildup of plaque in the arteries and stays in the blood for years, increasing the odds of a heart-attack.)
• One of the men Dyre has been monitoring is scheduled for a transplant in 3 days. He needs a reliable team for a rush job that will be incredibly time sensitive, and guess who he's worked well with in the past...
• "Go pick up this extortion money. I suspect a trap so I'm paying you ¥X if everything goes as planned, and ¥X+(Y% of the money) if it really is a trap."
• "Someone is using magical means to threaten and extort Mr Johnson, find him and neutralize him.

Meh.