Went with a Vortex 525 aluminum 42T.
The pro's:
No issues with launch, can't tell any difference.
Where I was in 3rd I'm now in second, etc.
A lot smoother around town and highway riding, real noticeable.
Was going to take 2 links out but there's plenty of adjustment left.
The cons:
(I hesitate using "con's" because it's just some differences that I don't mind)
On spirited twisty riding I had to modify my entry/exit in turns just a wee bit, by the second turn I was dialed in.
Overall it just made my XR THAT much more fun to ride so I'm not gonna complain about that. While it's smoother cruising around 400-500 RPM's lower than stock just ask and she will deliver, it's still stupid quick and fast. Very very happy with this mod

Now onto my next item on my list: Road 6's. The shop had a bike there with a new set and...well...I got excited.