Attempting light install. whats the dealio?

[gchurchill]

so yea, i found some online at - http://hummer.autowebaccessories.com/store/h3-roof-mark...d1309_1316_13005.php

they are 465.00. so I am considering this as to paying an extra $500 some bucks for the dealer to install them. Seeing that I have installed suspension kits and whatnot in the past, I dont think it should be too difficult. Has anyone else attempted this that has had some luck? I remember reading in the past someone that had a tough time with the actual install of the bolts in the roof. I am not skered to drill in the roof, I just want to know what is being used to secure the actual plastic rack to the roof? as I recall, only really hearing about problems with that. so does anyone have a little more information about that? it would be really appreciated to get some input either good or bad. thanks guys!