I installed one 4 years ago in my Charger myself. It was easy and I hate working on transmissions. Couple of dimples with an air hammer for the driveshaft hump and it was installed in about 12 hours. Helps if you have a friend with a post-lift or have one yourself. Luckily I managed. my 3.55s with a 28" tire took me down to 2600rpm doing 80mph. I drove it across country from California to Atlanta in three days and I didn't have one problem...Still don't.

Looking back...even though I love it...I wish I went with a manual gearbox if I was gonna spend the coin. I bought mine about 2200 through a deal on this site when it came around. Would have preferred the 5 speed but I can't go changing it now.

As already mentioned, split-shifting the gears is a PITA. I could never sync it correctly. Syncing from L to H in one gear is fine....changing from H of one gear to L of the next is the problem. I typically just toss it into Auto on the switch and leave it be. Some people put a dash switch to turn it on and off, I just installed the footswitch that came with the unit.