Yeh I have installed 2 intercooler kits for myself and a mate. It is quite easy, however for someone like me it was time consuming.
It all bolts up, except you have to drill a 3 inch hole in the front right of the engine bay. That takes a bit of guess work to get exactly right. Another thing is the front bar modifications. If you don't have a 400r or equivalent then obviously the cooler wont fit behind it. For me that was when an air-saw came into its own. Awesome piece of gear, couldn't have done it without it.
I would recommend doing it yourself, and if you got the polished pipework with the s type HKS kit then I would be very careful as it scratches like an motherf#$#er!!!