The PERRIN TMIC is big, but should not have fitment issues. Previously you might have had to reclock the turbo, to make it fit better, but we made a revision to the intercooler a year or two ago so you don't have to!
The PERRIN intercooler is a great working interooler for the 08+ WRX and is the biggest and freeest flowing intercooler that can fit without having to do major modification under the hood.