[baldlobo]

First off for the record all chrysler, dodge and jeep products are MAP.

Second i've thought of this too; it might effect top hp by 2-3hp(the decrease in size is 8mm(0.32 inch)); it will increase vacuum and decrease throttle response.

but what the peanut gallery forgets is we're here for mpg increases not hp(most of the responses are from bench warmers).

i don't think a heavier spring will do anything other then help keep your throttle from jumping around on bumpy roads.(ps. i have one because wpg roads are crap)