I have Dinan Stage II. I have a whole history tuning cars both my own and others at a good friend's performance shop, but I won't get into it because it never seems to matter what anyone's creds. are. in these discussions. For me, piggybacks and handhelds (with the exception of Cobb OTS tune with their handheld or custom done by Cobb) are a no go. I much prefer a pure ECU flash from a company that has a lot of experience with the particular engine I'm tuning. I considered ESS as my buddy is a dealer, but I chose to go Dinan instead. I couldn't be happier with the results as it seems to be just the right amount of power for this car and my intentions with it. IMHO and personal experience, "feature rich" translates to "more ways to blow up your engine". There are SO many self-entitled "experts" out there screwing around with things they have NO business f***ing with and that includes some so-called "Performance Shops" who sell\install piggybacks and handheld tuners. Go into any American BMW forum and just click on the Engine forums, hell stay in the model specific general discussion, and there will be 7-10 threads having to do with "Installed JB4 (or MHD) and 'x' happened, how to fix?".
IDC what anyone says, the dealer can ALWAYS tell your car's been tuned whether that's by flash count (yes, MHD flashes count) or past running parameters stored in the ECU. They can and might use it against you in the event of a catastrophic failure. Is it legal? Depends on your view of the Magnusson Moss Warranty Act (U.S.), but not really unless they can prove the tune caused it. Are you likely to win that debate with the dealer? Nope. Are you likely to win at all in a legal dispute? Nope. Are all these people who have no issues getting warranty work done with a tune on their car liars? Nope. Most of the time, if you're not a dick, they don't go looking for excuses to nail your bank account to a wall. But, no matter which way you decide to go, you're taking a sizeable risk. Even Dinan (carefully read the fine print of any of these tuners' warranties, should they provide one). That said, I'd rather have a good chance at someone else besides me paying for a blown engine than no chance at all. That, to me, is worth paying for (Dinan isn't even expensive anymore).
OP, since you track your car that often, should you choose to tune the car via any method (and I can't stress enough to the haters that are going to jump on me for this post how little I truly care what he chooses to do), I highly recommend the installation of supporting mods such as a larger intercooler and oil cooler. If you're just some idiot like me who wants more power and simply drives aggressively, you really don't need them below a certain threshold.
