Probably the biggest thing you can do to insure the longevity of the trans [and motor] is to have the right gears out back. It kills me to see guys build high powered motors and use manual transmissions but keep the crummy granny gears in the rear. That strains everything and eventually something is going to break. If you can mulitply the transmission first gear and the rear end gear, and get as close as you can to a 10 to 1 ratio, then you are doing the drive-train a huge favor. At that ratio it takes practically no clutch slippage to get rolling from a stop. Acelleration is crisp and the motor can do what it does best. Parts last longer.