how to tell if JB4 installed on pre-owned e92
how can you tell if JB4 was installed on a pre-owned e92 335i?
my 335i seems to be faster than other stock 335s ive driven. i dont want to buy JB4 if it was already upgraded. pictures of where to look and what to look for would be appreciated. technically the previous owner could have reprogrammed the ecu and then resold the jb4 unit or do they have to have it still on for it to work?