The 3300 engines came stock with 9:1 compression but had cast pistons and weak rods. The block, crank, and heads should support boost without a problem. There might be an issue with the stock cam because I think it has shorter exhaust duration than intake which is opposite what you want for a boosted engine. I would say you could probably safely run about 6lbs of boost if your timing is in check. Beware of detonation w/boost on those cast pistions. The 3300 has a 3.61" bore and 3.31" stroke compared to a 3800/3.8's 3.8" bore and 3.4" stroke.
I have actually heard good things about the reliability of the 125-C 3spd auto transmission. These tranny's are frequently used in V8 fiero conversions and I have had personal experience with a 3800 Series 1 SC swap into a fiero with a 125-C. This tranny really only had 2 issues, the TCC solenoid and 2nd gear band burnup, both which are servicable in the vehicle (providing you still have 2nd gear). The 2nd gear band problem that occurs is usually due to an incorrect length 2nd gear piston pin. While you are checking, or having the pin length checked, you can also see if your tranny has the better 2nd gear piston installed. Most of the 125-C's I have seen have not. The better piston that is availible has much of the same effect a corvette servo has on a stock 700r4. (i.e. better 2nd gear shifts).
