Fortunately there are several solid tuners out there with many of their clients happy with the results. I say what your best bet is to purchase a tune that simply meets your list of requirements.
Do you need a tune that you can flash yourself?
Are you ok with mailing out your DME?
Do you plan on getting future exhaust/intake mods that would benefit from a "retune"?
How much do retunes cost
Although I haven't tuned our E90 M3 just yet. I chose to go with Evolve Automotive for their evolve-R tune for my E46 M3. The biggest reason being their experience with specifically the DME of the S54. Their evolve-R gave me the opportunity to be dyno tuned remotely and very efficient. Evolve is also working on a way to implement data logging and reading/clearing codes through their evolve-R cable. For the price, it was rather an attractive package. In addition, Sal@Evolve was willing to personally call me from the UK and discuss in great detail how he manipulates maps within the DME. Every other tuner I spoke to did not answer my specific questions or really beat around the bush. I tend to be a consumer that wants to know the intricacies of everything and the reason behind the engineering. Sal was willing to share that with me and teach me a lot, while others refused to answer my questions or assumed I was an un-educated consumer.
Despite what route you go, whether Evolve, ESS, OETuning, Powerchip, etc...I'm sure you'll be pleased. There's a lot of competition when it comes to DME tuning which is great because it pushes all these tuners individually to keep improving upon their product. I would recommend to call every tuner you're interested in, pick their brains, see what they offer, see how they answer your questions, and then decide.
I think it's safe to say that most tuners are pulling similar power. I think what differentiates them is how they treat you as a client, the process of getting tuned, and what promises they have for the future.
All the best!
Last edited by flipm3; 07-25-2011 at 04:15 PM.