My F10 M5 with a Full RPi GT Exhaust is probably the most powerful without a tune or other power making mods.
I challenge anyone with an F10 M5 to a race who only has exhaust done. I'm currently making about 20-30hp and 40tq over stock.
As for F10 M5's in the U.S. with tunes, this is a crap shoot right now. Mainly all of the F10 M5's with tunes are all in Europe right now. I haven't heard of any tuner yet, and I mean any; ESS, Switzer, Dinan, VT Engineering, AC Schnitzer, G-Power, etc etc, talk about how their tune is GUARANTEED NOT
to void ones warranty in the UNITED STATES!
We're not talking about Europe here, so don't say that MHS has this or G-Power has that, because those tunes won't work in the U.S. or haven't been proven to NOT void your warranty. Word on the street here in the U.S. is that no tuners can crack the ECU codes yet for the F10 M5, and even if they did, there are rumors that BMW has figured out a way to detect if an aftermarket tune is on or has ever been on your F10 M5, and can then void your warranty. So right now I think that it is a huge gamble with some of these early tuners offering tunes for the F10 M5. Any power that "some" tuning company makes on an F10 M5 with an ECU tune will be worth nothing when that F10 M5 breaks or its warranty is voided. Not worth the risk right now. I want to see indisputable evidence that BMW will NOT
find out there has ever been a tune on your F10 M5 and that it will be 100% reliable. This usually involves thousands of hours of extensive testing, similar to the kind of testing that ESS does. If any tuner can show me this, I will then show them the MONEY!!!
So for now, Race Precision Inc's (RPi) mission is to achieve as much power as possible with only bolt on mods until a reliable tune comes out. And so far a gain of 20-30hp and 40tq over the stock system is THE MOST
that I have ever seen published from just an exhaust system. If you don't believe me, then lets race.