For a 94 Z28 auto.

 

That depends on the type of tune you're wanting.

If you're wanting to send your PCM off to someone to be tuned, or them send you a tuned PCM and you return yours to them, then either Madwolf or PCMforless will work. They're priced similarly and both have good reputations for good work. Ed Wright at Fastchip also does tuning, but he used to "lock" the tunes by rearranging the table locations so that other tuners couldn't mess with his tunes. The other guys don't do that, so if you decide to do your own tuning later, you can.

If you're wanting someone to work on a tune specifically for your car, where they are actually present to do the tuning, that gets more expensive as well as time consuming.

There's also the possibility of you purchasing tuning software and doing your own tuning.

 

Both of the mail-order tuners mentioned above (madz28 and PCMs4Less) are very good at what they do. I personally went with madz28 because he was cheaper at the time and the results were very impressive for the amount of money spent. Its definitely a cheap and easy way to wake up your car.

 

FYI, he doesn't do that anymore.

 

So what can these guys do to the PCM to bring more power out? Can they mess with the timing or just rpm's and shift points and such?

 

They lean out the A/F mixture, adjust shift harshness, coolant temp. fan on/off adjustments, and advance the timing a few degrees, but I believe this is if you only are willing to run premium gas. There are other things they can do as well, for example, Madz28 did an "emissions compliant" tune for me where he got my EGR valve to function properly after the long tube header install. If you have questions, his site is very informative on what exactly he does to tune your PCM and he is very good about answering questions.

 

Hey dont forget tjwong on here too! He owns a Dyno shop and does all mine now, and I own a custom auto shop. I went to tjwong when madwolf had some issues for a short time and had to shut his tuning down for several months, and I had a couple LT1 Swaps in my shop I had to get done, I know both you mentioned are very good too.