I just installed mine on sunday in my driveway. Just took a couple hours. I'd say the hardest part by far was getting the rear o2 sensor out of the stock exhaust. Just get an o2 sensor socket, spray it with something to get it to loosen (i used PB Blaster), use a breaker bar/cheater bar and a foot and you'll be fine. Other then that the only hard part I had was getting the round gasket off the o2 housing (you have to take it off for the downpipe to fit... it's all in the directions though). I don't know if anyone else has any better tips for you on this one but i just got a thin flat head screw driver and worked it under the gasket and pried it off.
Goodluck