i drive a 3.8 97 camaro w/ flowmaster 50 series. my buddy has a 4.0 v6 deluxe mustang i pretty much know the numbers as far as weight, torque & horsepower. he probably could beat me in a race cause his car is brand new and optimum running condition. although i did have a major tune up done + new tires. i was thinking about changing my rear to a 3.73, and i think that would give me a great advantage but im not sure if i should only change the ring and pinion or should i replace all the bearings, bolts etc. the rear end is $220. and the kit w/ all the fittings is $123. im not trying to spend a fortune and would only buy the fittings if i had to. which route should i take? (72,000 miles runs superb)