[ViperBoy2]

Just bought a 2015 X5M with Dinan stage 1 + exhaust and 22" wheels. Car drove great for 400 miles but needed tires so I replaced all four with alignment (Toyo Proxes that do have a 1.3% size diff but are used by several people on various forums). A day or 2 later we noticed a pull from side-to-side under medium-hard acceleration a couple times but didn't have time to get it checked out before a trip

In the hills this happened several times (fairly hard pulling and then the engine felt like it was between gears and sounded a loud mechanical whine, before a hard clunk shift up). I limped it down the mountain. Disabling DSC lessened the side-side but not the power problem. Tried getting on the freeway and it wouldn't pull over 60MPH and so took side streets to the dealer in Chico, CA where by the time I arrived was constantly cutting power. The check engine light is NOT on and one time I got the power cut screen error but restarting the car cleared it (but not the power cut)

However, the dealer cannot hook his diagnostic tools up because the Dinan ECU seems to be interfering with the system (even though the reason Dinan charges 3k is to allow BMW techs to work on it!). I noticed that Bimmercode app with an MX adapter also couldn't sync with the ECU so I believe their problem is possible. E-Sys with a enet adapter was able to read various ecus though (never tried ISTA)

Any ideas on what this could be or how to get the Dinan system to behave? The dealer tech hadn't seen any piggyback problems before, but wasn't an expert on them and so didn't know what step to take next. I'm thinking it needs either a bmw or dinan flash upgrade or remove the dinan (which they don't know how to do) but if this problem sounds familiar, maybe I can have the problem solved.

I'm now 200 miles from the car and would like to find a way they can fix it in Chico - otherwise I need it towed to back to Bay Area (mega $$) to the Dinan dealer here

TIA...