Give it 60K miles, it's a caddy engine, dont expect it to be reliable. I'd take the 3800 intake leaks over the caddy piston ring problems any day. As for tranny problems, we've already had one LaCrosse come in the shop with intermittent shifty problems, had a rolled seal on the number 2 or 3 clutch i believe.
As for the car overall, i'm very impressed with it.