302's are just as responsive to mods as any motor. GM just put WAY better heads on the 350's. The first thing I would do is brace the car up, subframes and a strut tower brace at the very least. Then get a really nice set of aluminum heads (AFR, TFS,etc.), headers, off road H or Xpipe, and a chip or reflash the ecu. Actually, I would tear that crap fuel injection right outta there and slap in a good ol 4bbl, but thats just me.
As for the motor itself, Im runnin 11:1 compression on mine on the stock lower end which has better than 130K on it, there is NO problems with the rods, and I drive my car really hard. If you do go more than Id say 400 horse you definitly wanna hook the motor up with the 4 bolt main caps and maybe even a girdle. And the T-5/T-45 trannies are CRAP! Ive blown up soooo many of em, bearing failure most of the time, and when those failed they'd mess the case up also. Id estimate good tranny capacity hp numbers in the 300hp range, theyre VERY weak, in my opinion.
-P.