I recently installed the Super Chip into my 91 RS 305 Man. and noticed a great increase in performance and then went with the switch idea of turning my speed sensor off, but i notice i have a harder time going over 85 miles per hour with it off, but not so much as with it on. is it the chip and switch conflicting or is it the fact that i have a ghetto rigged exhaust and the car needs a tune up(i know the exhaust and tune up are important, but is it really that important?? thanks for any info