What is involved with a 3:45 gear install? Is this the kind of thing that can be done by the novice with the right tools and instructions? Anyone know where I can find instructions on changing my gears on a 1990 T-bird. What else is involved? Will I have to change my speedo or do any tuning to swap new gears? I figure these are my best bet over my current 3:27s since I don't wanna go too steep because I do use the highway a fair amount.