I was also iffy about the backend flash for about 4 months. Your thread helped me decide whether to do it or not and I have no regrets since! I will never go back to the stock flash.
I’m in IL and ran 93 for premium and e30-e40 for e85 mix before fuel pump upgrade.
I now run e60 with a stage 2 pump
My experience so far is that on stock flash, car felt great, but very inconsistent. You also felt like you were really “pushing” the car to its limits everytme you floored it. Gas mileage was around the same as stock and it was fun, but flashing really did make a difference. I was eating injectors as well (index 8) and would constantly be logging to make sure everything was okay.
On Pump flash, the powerband felt so much smoother. You didn’t have that strong “kick” feel you did with the stock map, but the speed was essentially the same and the cars powerband felt much more natural. Definitely had no regrets doing the flash. My main problem with pump flash was that I couldn’t see peak boost levels over 15ish on map 5 and I felt that timing was a bit low for the fuel I was running. Gas mileage was also far much worse than with the stock flash for some reason. Worth it for pump users forsure! Car felt like it came with 15psi from the factory.
On Race flash, my car ran amazing. I usually run about a e40 mix and keep it on map 5, and my logs are pretty much perfect. I got that nice kick feeling back that I had with the stock flash, but my powerband felt 10x more smooth and the car pulls consistent everytime. Timing is much more aggressive and I’m seeing nice boost levels on map 5 that were very similar to the stock map setting and much better than pump settings (16-18psi peak on map 5). It was definitely better than both the pump and stock flashes. There were even a few times where I was forced to run just 93 and the car detuned itself safely. The only downside was that on map 1 and map 2, timing was still real low, close to pump flash timing, and I really just saw a gain with map 5. Still worth it though!
On the e85 flash, I was expecting a huge difference since timing was suppose to be more aggressive and I had a stage 2 fuel pump now with more E content. Honestly though, it was very similar to the race flash. After the car fully retuned itself, I did feel a slight power increase and I am very happy with the flash, but if you’re running the race flash it is not TOO much of a difference. Every little bit counts though so I am still on the e85 flash
. You can also run map 7 safely with the e85 flash and e60+ fuel so that is another advantage, although I love my map 5.
I’m dynoing my car Friday so I will also share those results for people who are curious.
To wrap up, I agree with the OP. Do the FLASH! If you have that special Bavarian tech cable or whatever it is, you can do it free with Windows. If not, all you have to do is pay like $60 bucks for MHD flasher license and you’re good to go! Worth it. I even passed IL emissions with the flash on.
Hope this thread and my post helps someone make a decision like it helped me!