It isn't all that bad - once the dash is out and it's all apart, it makes sense to do it. I replaced the core on mine and put it back together having not tested my 'repair' on the passenger heat motor. Then spent the summer wondering why I didn't do it when it was in bits. Now I need to take the dash back out before next summer (or see if it's workable through the glovebox hole but probably, it isn't). The only part of the heater job that was looking to be problematic was getting it out from the metal frame in the centre above the transmission tunnel, turns out the large bolts (4x) that go into the floor will allow enough wiggle room when loosened to get the top unbolted and pull the top half of the heater out and off from the a/c bit. Quick edit - looking at my photos the entire silver-grey middle frame came out leaving only the car-coloured bits.