Oh it is a royal PITA, don't let anyone tell you any different. I am a professional tech so, even with a lift and professional tools, it took me about 4 hours to install. The hardest part, I would have to say, would be removing some of the hard to get to lower bolts on the bottom of the stock manifold. They are a little easier when you put the new manifold in (hell you can even flat out see one you couldn't hope to see on the stock mani) and I would say it was definitely worth it.
I have the Cobb AP, so originally I was scared by the Cobb "softies" (it's probably just liability reasons but, for Christ's sake, they don't have a pair between the whole group that works there) about whether either one of two tunes would work on the car when I installed it. Originally, to be on the safe side, I started with the Stage 2+ MSCAI tune (intended for a car equipped with a turbo-back exhaust with CATs). I found it ran really rich (about 10.4-10.6 at initial spool), boost spiked to about 21psi in 5th (20psi before) and really did not feel that much faster. I decided to run the original tune I was already on (Stage 1+ MSCAI). It hits a little over 12 A/F on initial spool (might be due to the super slow refresh rate of the Cobb AP) but then meters out to 10.6 near the end of the power band (comfortably rich), spikes to 20.6 psi in 5th, and never even flinches on the Knock Retard. The car feels a lot faster on this tune. So for those out there with a Cobb AP, don't be afraid to go against what Cobb suggests, because I'm sure I'm not the only one who thinks they are very, very conservative. Of course, I can't blame them with all the lawyers and liability in America.