I ran the Grimmspeed intake mani, exhaust mani, tgv deletes, and phenolic spacers on my wrx. The one thing that you'll notice the most is throttle response is greatly improved. Power wise your still going to be limited by your turbo, but the vf48 is a wonderfully cheap used turbo. You'll def like the new found power. Just up to you if you want to spend the extra money on pnp work.