Ok so here's the deal. No-one can make an absolute promise that anything is "undetectable". Technically it is actually but it's not possible to guarantee that. The JB can be removed, faults deleted etc, and there will be ZERO trace that it was in.
The FASTA thing is misleading, they cannot check what boost the car ran. FAST can check if you exceeded any limiters & it logs those specific events. It can't check boost live or recorded. If you have a fault like underboost/overboost then that fault is logged (not necessarily even with FASTA), but faults like that can occur even on a stock car. If you have a tear in your vacuum hose, it can throw a "boost theshold - lower limit" fault. Doesn't mean the car is modded. Even limp mode faults or misfires can happen on stock cars.
The only faults that prove a car is modded is the "tuning manipulation" fault but all the tuners have licked that a long time ago. And also the dealer can't check that the map is changed if you have a flash tune. Absolute hogwash. Dealers don't have tools to go into the code of the map and see what bits and bytes are different to a stock map. They can't even see what's in the map. Al they can do is check faults, update firmware, etc.
But bottom line, absolute bottom line is that is is your car. You are paying for it. If you have ANY doubt, any fear of losing your plan, then don't mod it. It's that simple. But don't go blaming tuners or BMW or your neighbour's cat if you lose plan. I know of people that lost their plan on stock cars. So if you choose to mod accept that there is a possibility you may lose your plan & live with it because you want the extra power.
