[Lark]

Do not buy that ebay ripoff. Lurcher is right though, you can't have more horsepower and better gas mileage.

Dinan, JB4 and Cobb are the most common tunes discussed.

Go to Bimmerfest, e90post or N54 tech and you'll find the merits of each debated ad naseum.

The JB4 is not being sold in Cal. because of CARB standards. As I read their website it is illegal in Cal. And presumably in the other 12 states that have adopted Cal. CARB standards. And as I understand it, the current plan is for the feds to adopt Cal. CARB standards, so JB4 could be a problem. Also JB4 potentially creates warranty problems I wouldn't want to deal with.

Dinan has a warranty that mimics BMW original warranty. Dinan will pay for anything that breaks that BMW won't. Many BMW dealers are authorized Dinan dealers.