If you want noticeable acceleration improvement that won't cost you more in fuel go with a lightweight driveshaft.
I have heard from everyone that has ever had one that it's a noticeable improvment in performance: kinda helps the car rev faster; less rotational mass thus allowing more hp/tq to the rear wheels.
'97 Cobra Vert - sold
'06 GT Sold 6/2010
Current: '06 F-250 Diesel, '10 CR-V, '11 Civic (Lease)
Ordered 12/12/12 Built 1/25/13 dealer received 1/30/13
2014 GHIG V6 Stick w/Perf. Pkg