It is sort of easier to remove the trans with the engine, but it isn't necessary. If the car is on stands, support the trans while you disconnect the bellhousing and torque converter, and then slide the engine forward. Mostly it is pretty straightforward to pull the manifolds off and lean them away from the engine. Remove the accessory drive brackets on the left of the engine and get those out of the way. Remove the mounts and any necessary wires, and yank it out.

If you're careful, you can get away without disconnecting any A/C lines, so you don't have to worry about having to recharge the air conditioning. The radiator should come out along with the intercooler (if so equipped).

Overall the job is not hard. If the car is elevated properly you'll have plenty of room to work underneath. Some of the bellhousing bolts you can get to from the top, and you shouldn't have any problem from there. The starter can be a pain in the butt, but not bad. The worst is getting the torque converter bolts out. Those can be difficult (but again, not impossible).

Good luck.
--
Chris Herbst, near Chicago.