First of all it is great to be part of this forum! I have a 2006 550i with steptronic and want to get the most out of the V-8. The forum is so full of information and different opinions that iy is difficult to sort through. I am torn between the Dinan S1($$$) versus separate CAI/Sprint Boost?Chip/Exhaust but would lose out on the suspension upgrade. All input/opinions/thoughts are greatly appreciated. Great to be here!Click here to enlarge