As I understand it, it has been done and yields some gains (20-30whp IIRC depending on octane), but they are minimal compared to the cost...
The cost of the CJ IM itself isn't much but it's not compatible with the 350 TB, so you need to buy the specific TB it works with... If I recall right, all in you're gonna spend in the $1600-1800 range for the pair of them and that's before a tune.