How hard is it to replace tranny?

Just wondering how difficult it is to replace a tranny in an 04 grand prix gt1. I've had serious shifting problems and now it won't shift hardly at all. I dropped the pan and found the magnet full of metal shavings so I'm sure it's damaged. I think the pcs is damaged or something. Will replacing the tranny solve my problems?

Support the engine, remove the lower subframe which requires undoing the ball joints, rack and pinion. Then you remove the axels. Then the starter, access panel and torque converter bolts, and the the bell housing bolts....

Its a pretty big job, and a major PITA if your doing it in your driveway.