u should be good. Changing the trans and diff to redline is not very expensive at all. U need 2 quarts of 75W90 for the diff and 2 quarts of D4 ATF for the trans. The redline will run u roughly $8 per quart. A shop should not charge u more than $40 for labor. When was the last time u flushed your radiator? Did u change your Fuel filter at 60K? One more thing, flush your brake/clutch fluid. :)