[IaHawk]

Im4citadel - I'm getting late into the conversation but as to your question whether the Dinan upgrade is worth it? I would say it depends on what you value most in a car. Over the past 13 years I've had a 2000 M5, a 2008 M3 and recently went with a 2013 550i xdrive m-sport with Dinan mods including S2, free flow exhaust, and the supspension. I was able to do this for roughly $74,000 (Dinan mods added roughly $8000 to the $66,000 stock price). I like the M cars, but I live in Wisconsin and got tired of doing wheel/tire swaps every winter and wanted to go with all wheel drive. Plus as others have pointed out, there is about a $25,000 difference between the car I am now driving and an M5 - it was a no-brainer. You can argue all you want about the differences in performance but the bottom line coming from an M car enthusiast is the all wheel drive for me trumps the performance differences with the M5, the latter of which I think would only be noticed by professional drivers on a track and would still be fairly small. So you have to look at the price itself in my view - that is unless it is the M5 badge you value most.

There is a world of difference in my experience between the stock 550i and the car I have now. The big question is, would there be much difference if I upgraded to the S4 with intercoolers. Upgrading to S3 would only cost me about $200 since I already have the exhaust but that would only add 10-20 hp. But S4 requires the intercoolers which will be a few grand and might add another 40hp over what I have now which is about 510 I believe. I doubt the difference in hp would be that noticeable in average driving, but my understanding is the benefit of the intercoolers has to do with protecting and prolonging the life of the engine itself against the effects of heat with aggressive driving - the Dinan folks believe the stock intercoolers are too small even for the stock version of the 550i. So I find it interesting the comments that the larger intercoolers would overstress the turbos - it seems the main argument for the intercoolers is to provide better protection for the engine in general against aggressive driving especially in warm climate.