We've done 6 Lemons events to date going back to 07 with our 7th race being at CMP at the end of the month. During that time we've built and prepped 4 cars (early 90's BMW, late 90's P71 Crown Vic, 99 Buick LeSabre, and our current 97 Pontiac GTP), and the most expensive one to date has been the GTP. We spent more on upgrading the front brakes than we spent on the car itself, while that might seem insane it was worth its weight in gold on the track. We also paid to have a top quality cage put in since the one in our last car was substandard at best.
As for finding a group of crazies to join you in this venture, this will probably be the hardest part by FAR. Any team can tell you horror stories about trying to fill a driver slot, when you put the word out you'll get a lot of people interested until they find out they're expected to actually put their money where their mouth is. If you can afford it, I'd buy everything for the car yourself that way it's your car and yours alone, then you simply charge the other drivers a rental fee which will cover brakes, gas, tires, ect ect. It's what we started doing this year and it's worked out very well for us.
If you want advice on a reliable car that will run all weekend without problems, then I'd strongly suggest looking for a late 90's GM FWD car with a 3.8 under the hood. They're not the most powerful or highest revving engines out there, but they will take a pounding and ask for more. Take it from a team who's run both NA and SC versions of the engine.
Team Final Gear Crew Chief
#138 1997 Pontiac GTP - Supercharged 3800
#42 1999 Ford P71 Crown Vic