Someone did on this forum I am sure of it but I cannot locate the thread. I was actually considering it at one point as well but then decided against it. I really wish I had more info
So are you saying that you removed the pumpkin, opened it up, and swapped just the ring gear inside and that was all?I did, and did a write up of a 2.0 track in a 2.0 base (you can just ignore the opening pumkin part), but I am waiting on tech exchange to publish it (maybe if you bug them they will get it done faster lol, it has been up for a good 4 weeks now). The speed sensor is on the wheel/rotor itself, so no change there. IIRC, the 3.8 and the 2.0 are transferable, they have a differnt final drive's, but nothing different you have to do, just be aware of it and how it will affect performance/shift points ect.
IMO, the ring gear swapping ect was very easy, maybe took 30 mins. Getting the pumpkin off was the hardest part lol. I gave it a 9/10 for me on difficulty, but a 6/10 for anyone with experience, and a 4/10 for those with the right tools, a car lift, and experience.