Pre 08's will last longer at 350whp than 08+ cars. The pistons in the pre-08s are nothing special and will crack ringlands eventually... but the 08+ pistons are an embarrassment. I cracked a piston on stage 1 and cracked a second piston on stage-2 (2011 sti).
350whp is a lot of power no matter what, and you will be on a relatively short countdown to rebuild regardless of the year. Really depends on how abusive you are. If you want 350whp and you want to hammer the !@#$ out of the thing at every opportunity, build the block.