Removing the bumper is really the only way to take the intercooler off.
Start off with the two bolts inside the wheel well on each side, they're 8mm IIRC, watch them because they secure into plastic clips on the back of the bumper cover. They often rust and seize and end up tearing out of the plastic. Count on having to use some assorted hardware to fix this when you are done.
Check under the front lip. Most of the bolts holding it to the frame will probably be torn off, but if there are any, remove them.
Remove your foglights if you'd like a little more room, they are one plug and two 13mm nuts under the bumper support.
On those same bumper supports you will have 3 nuts to remove on each side. Two are on the upper front at the top, on each side of the support. One is on the rear on the otherside of the frame, on the outward facing side of the car. Hit all these nuts with WD40 first, it'll make your life a lot easier.
The one nut you will have big problems with. The passenger side inside nut on the front is blocked by the intercooler piping. You'll need to fiddle with the piping to try to get in there, and its going to be very tight. You'll see exactly what I mean when you get there. Unclamping all the intercooler hoses can help so they can be moved around somewhat freely.
Note once the bumper is off there may be some shims on the support bolts, try not to lose as you remove the bumper from the car. A slight outward tap once everything is free is enough to send the bumper to the ground, so be careful.
The intercooler itself is held on by two 10mm nuts bolted to rubber standoffs. WD40 these good, because if they are seized you can tear the rubber standoffs in half. The other side of the intercooler has two bosses that fit into the center header panel support, so once the two 10mm nuts are removed the intercooler will just slide out.
You might want to have an extra hand around while re-installing the bumper as it can be pretty frustrating to get back into place.
I think thats about it. Be careful of your front lenses with the bumper cover off, its very easy to lean onto them and crack them (done that too many times now)
Hope this helps.