welcome along will.i'm also looking into doing this to a 323i e46.from what i can make out you get a lot more power out of doing it to cars with turbos.i was told for mine i'd get 190bhp,its 170 bhp as standard.they also told me i'd get around 3 to 5 extra mpg and all that on a car without a turbo too.as far as insurance is concerned quite a few companies will charge more if you tell them about a remap.if you dont tell them and you gob it they apparently can tell if it has been remapped so be carefull. i've also been told that it does no harm at all to the engine as long as the remappers know what they are doing.haha. hope this helps