Your information may just be correct.
You can get part throttle surging and bad drivability from a front mount and long tubing with smaller turbos.
I don't run one but have read about it so you might want to hear from someone that's had that combo for the details.
Old school Kenne-Bell "big boy" is a smallish front mount you might consider.
Old school by today's standard huge ones but just might be perfect and even cheap to get ahold of for your car.
Don't have the dimensions of that model but a search on the internet might find it.
Perhaps even a stock GN intercooler or a stretch stock location could be front mounted cheap enough, don't forget the big neck option for it.
There's a good hybrid section on another board, Turbo, buicks .com
Use the search feature on all the boards to look for dimensions.
Good luck.
