Dawg and Big T: Dinan has a rear diff with 3.73:1 ratio, which I installed on my 95 740i several years ago. MUCH quicker with this. The only "price" you pay is lowering the top speed some, but then I haven't been in the habit of topping 150 mph frequently anyway. The mileage really doesn't suffer, I get 24 mpg freeway. Your buddy with the 98 sport will be watching you go by...