I know it's a little late now, (sorry), but sometimes spraying the bolt heads with something like PB Blaster... and letting it soak for a while,,, then starting the engine and letting warm up partially... is enough to unlock the bolts from the threads. Not up to full temp... but enough to get the aluminum to expand a little. Maybe half way to full warm up... then shut it off.
Again... sorry.
Now that you are where you are, (if you decided to try to pull the intake to fix the busted bolt):
http://www.irwin.com/tools/screw-bolt-extractors/35-pc-screw-extractor-drill-bit-set
You're gonna want the 5/32, 3/16, or 7/32 multi spline extractors . I think you can buy them separately. Also a good set of cobalt drill bits of appropriate size to be slightly larger thane the tapered end of the multi spline extractors. Your also gonna need some sort of thermal blanket, (like sold in the plumbing area of your local big box home store), used for soldering copper plumbing.
Once you get the intake off,,, get everything out of the way near the busted bolt... and cover everything around the bolt with the thermal blanket. Using a small propane torch... head the head slowly, (around the busted bolt) ,,, and occaisionally spray the hole with PB Blaster... letting the oil soak into the threads. While still warm,,, center punch busted bolt, (or do before hand)... then drill about 1/2" deep. Re-heat head around the bolt a little more,,, then use extractor. Go slow... and check for bolt movement... and that the extractor isn't twisting.
If you are willing... hope this helps.