For my money, its HPTuners. Custom tune or even a remote tune, no canned tunes....If your not going to mod your car, then there is really no point in getting a tune anyway, your lucky to get more than 20whp out of it.
If your an Auto, there is benefit in getting a transmission tune, but without mods, don't expect to gain much power. If I was going to rely on someone else solely to tune every aspect of my car, then I would go with Livernois. They are sharp, and have great products, not to mention their proprietary tuning software, is extremely capable. Infact, I would put them past most tuning suites.
What I like about HPT is that 80 percent of the tuning industry uses them, there is a bunch of user support, so if you get stuck and need help, head over to the forums, or ask a fellow member here who also uses and tunes their own car, and your all set. You may not want to mess with any of the tuning parts of your car your self, and thats fine, just keep in mind, most shops are using HPT. Not all, but a lot. So your chances being able to work with someone after you get your first tune is a lot better, If you decide you want to go to another tuner, you wont need to go and buy something completely different.
What I like about it is I personally make some of my own changes, in conjunction with my tuner. I am not strapped down by a tune lock, or software that can only be used by the people who tuned it the first time. Good luck, hope that helps.
Forged bottom end. AGP TT, Dual nozzle meth, ID850's, Livernois dual fuel pumps, ECS BAP, 25% UDP, 3 inch Magnaflow catback with X pipe, Mantic 9000 clutch, DSS 1000hp axles, DSS aluminum driveshaft, ZL1 rear end, solid subframe bushings, HE differential offset bushings, BMR Trailing arm, BMR toe rods, Lingenfelter LNC-2000,SJM Line Lock, and much more Built by, FSP, myself, and some a few others, Tuned by FSP and me 800ish whp