I have basic bolt ons. Long tube headers. Magnaflow Exhaust w/ X-Pipe. CAI. Check engine light is obviously on from the headers.

My question is, is it worth tuning? Guy I know who has a pretty good reputation for tuning in the Houston area will dunno tune it for around $300-$350. I was told it was bad to be getting on it without a tune. How much can I expect to see on power gains? Is it bad to be driving without the tune? Thanks