the difference between your supra and xstar wakes are huge. the supra is narrower and steeper, the xstar is wider and rampier, totally different. Since you have been behind your buddies bu and you seem to like it, going to the xstar will be only a slight change. The bu with the wedge has a lip and is steeper than the xstar, if you ride the bu without the wedge, the wake shape is similar to the xstar. I love that xstar wake, so I am biased. I say go get an xstar and keep adding weight til it gets good, then throw another 1000 evenly across that boat
To me the bu's (no wedge) and xstar wakes are the best. That is why I bought the boat I have.
with that said, your buddies bu handles completely different than the xstar. The xstar, especially when weighted, is a pig to turn. This is not a concern for most riders if you ride in a wide river or big lake, why do you need to turn easily? But for some of us that ride in narrow lakes with multiple turns and tight turn arounds, that xstar is a pain to drive, even more so when weighted. A 23' bu wieghted turns so much nicer and does not roll up on the chine (correct?) or whatever, the xstar does.
best thing is, go get a pull from an xstar owner, empty, stock weight, and loaded... drive it in all 3 scenarios. If you like it, and the price is right, do it.
curious, what is the asking price for the 04 star with 650?