nice looking p5! i've never seen that brand intake before, but it looks nice. i believe SLS may make a mid pipe that'll go in place of the second cat. if you're looking to build your n/a engine you'll definitely want to look into the Spicymsp's mp3 ECU flash. as far as putting $2k plus into the engine you may want to consider a MSP turbo swap, you'll see much more power gains and it's mostly all plug and play.