is a standard wrx intercooler the same as the sti one

 

Nope, it's smaller.

 

cant get much smaller than my sti 2 one

 

On another thread we proved pretty conclusively that, for version 4 models at least, the WRX and STi I/Cs were identical in construction and size. The cosmetic difference is that the WRX one is sprayed black and the STi one is left silver. The actual performance difference comes from the STi y-pipe underneath, which is made of cast metal. On the WRX, it's crappy corrugated plastic, which does present a real restriction to flow. A v4 WRX I/C with Samco hose kit performs the same as an STi one.

However, this is only for v4 models. On later ones, the STi ones are larger, but couldn't say for sure without checking them side by side.