XR4ti turbo, eh? You're good to around 300 hp.

You can run standard exhaust for now, but you really need to upgrade if you want to uncork a good bit of power. And a "free flow muffler" doesn't cut it - you want a straight through design as a chambered muffler does not work for forced induction.

AbaZ/Jeff is 100% on track with the FMU advice - don't go past 5 psi with it.

I've always been a big fan of boosting a bit in, say, third and then immediately cutting the engine and coasting to the side of the road so you can pull your plugs and check them for how they've been burning - you can catch detonation that you can't always hear by this method, too. If you try to idle to the side of the road, you ruin the reading. (Thanks Todd, I know you're reading this)