3800 motors are pretty reliable up to around 350ish whp. The real down fall in the FWD cars are the transmissions not holding up to all the power. Even the 4T65e-HD needs a fair amount of work to be able to hold that amount of horsepower. A supercharged 6th gen Monte Carlo ran a 12.6 with stock suspension and slicks.
Personally I would of been happy to start with a V8 if only my car came with one. I guess the FWD and RWD 3800 worlds are a bit different. But i did by the biggest motor available for my car. It might not me much but with a bit of work it will speed up. I'm still saving up to assemble my own turbo set-up rather then spending 3 grand on a kit.