I just recently replaced the blower motor in my '01 T&C with ATC. Tried everything I could think of for that last bolt against the firewall. Wasn't about to disassemble the upper dash to get at it though. As I had read on a post here, after a longer period of time than I would want to admit to in my attempts to get to the bolt, I took the frustrated DIYer's attitude and twisted and pulled unitl the rear ear portion broke off. Once I popped the recirculation door out of the lower housing, I found that a 1X3 section of the housing had broken off. Knowing that this was not an air-tight housing, it didn't worry me the least bit. Once the housing is re-installed, the broken piece fits the opening and is against the firewall so no one sees it and it has zero affect on operation. The hardest part of installing the new motor was getting the recirculation door to fit into the pivot point above the motor so that it moved smoothly and freely once the housing is re-fastened.
Side notes: Read on here about the cabin filter and replaced it as well. Cheap insurance to remove the possibility of a clogged filter from the equation. As for the motor, all the local parts stores had it (with the blower wheel) in stock for $100. Found it online and got it from RockAuto for $60 including shipping. Same part number but $40 cheaper.
'01 T&C LXi -200k miles
'84 Celica - 200K+
'95 Accord - 135K