Hmm... Well right now I have spd eng headers and ory to a 3" straight pipe to a xr1. I think Id have a tough time getting to 400 rwhp with that. For dual 3" id have to wait for spd eng to begin shipping but its cheap! The SW 2 1/2 systems almost seems perfect but its pricey, however I think it would make the best average numbers/torque/ and sound. Not sure what to do??

 

im putting down somewhere between 330-350 NA and there have been PLENTY of people making well over 400hp with a blower or turbo that run a single 3".

I would honestly keep what you have.