its easier to drop the pan when its in the car. so if you do it or the shop does it, it really dont matter, as long as it gets done.

and to be honest, id make sure it moves before putting 50 bucks more into it. if it drives, shifts, and it seems to be working well, then do the fluid and filter. if the trans is bad, you've just wasted 50 in new fluid and the filter.

trans mount would be a good idea too.