I did this replacement a year or so back. I did have to remove the Throttle body but did not remove the intake although I was almost ready to do it. I really didn't want to so tried one last thing...
You can get the rear two bolts out but it is a REAL PITA and if your bolts are a tiny bit longer than mine, then I bet you are screwed.
You just have to get an open end or maybe box wrench in there and turn it about 1/8 turn at a time, PITA like I said. Eventually the bolt becomes loose and wobbly and at that point it is no longer engaged with the threads of the top of the block. MAYBE then You can then wiggle and twist and tilt it til they come out.
Mine were removed this way but I wouldn't care do it on a regular basis. I should have, and you should now, cut off maybe just 1/16 inch of the bolt so it no longer hits the bottom of the intake, before you reinstall them. They are only a little bit too long so that is why I was able to remove mine with much sweat. BUT, dimensional tolerances and component stack up might go against you and the bolts will still be stuck. But no great loss since you had to unscrew them anyway, just a pita.
I don't know if this way is easier than pulling the intake, but I really didn't want to go thru the trouble of removing everything and making sure I had a good seal, plus I didn't think I could get a gasket set on a Sunday.
It can be done, maybe, but it is a chore.
Good Luck,
Jim Henderson