As above, what year WRX?
If its an earlier newage, it might still have a cat in the uppipe, so check for this. If it does, change for a decat uppipe - this can be done without a remap.
The PPP will have removed the centre (3rd) cat, so you'll just have the standard Subaru downpipe cat. If you go decat downpipe and fuel pump (can do TMIC as well) plus a remap and you'll be circa 280bhp (without changing injectors/turbo).
If you're going VF35, then add the pinks and remap. Headers still not necessary at this stage but ported oem headers will help a bit
