I also wont be going back to JMS. I had a great tuner that doesnt work for them but he did a great job. However they took 3 months to get me my files after several emails.
Modular Powerhouse did my tune when the car was NA. It was awesome. It was a totally different car. Idled better, revved faster and smoother. And power came on lower in the RPM range. HIGHLY recommended.
Not to say a mail order tune won't be without it's problems. No two cars are alike, and therefore you can't tune for EVERY precaution. Tim's tune was a little off at first. But he didn't know about all the past troubles I had with the car beforehand. But he mailed me another one while the old one was still in the car and I mailed the old one back to him. His service is impeccable. And his second tune was spot on.
It's the equivalent of buying a custom suit over the web. You can give measurements till you're blue in the face....but once you get the suit on, you'll need some tweaking. If you can't be there for a tune in person, expect (probably won't have to), but expect to send it back at least once for tweaking.
I still will only trust MPH with my car. Thinking about a mail tune for my F-150.