The Chevy 4.2 6 banger is a great motor. We just sold our '03 TB, it had 250k on the clock & ran just as good at 250k as it did the day we drove it off the lot.
Owning both the AMC 4.0 & the GM 4.2, I'll say the 4.2 is light years ahead of the dated 4.0. They have power out the ying yang in stock form, let alone with basic upgrades (a good performance flash will make them come alive).
I'm sure someone out there has done the swap, but it's nowhere near as popular as a V8 swap, so info is going to be hard to find online. IF you have the means & ability to do the swap, I say go for it!