You will probably want to do something to correct your speedo. You could get a speedo gear. That will not get you right on, but it will get you pretty close. If you want a better solution, you can replace the gear inside the transmission (although I think that is a lot of work). Or you could get a speed cal (about $90).
How's your trac loc? Any one wheel peel? It will be worse with the new gears. So you might want to rebuild if your limited slip is questionable. Also you might want to replace the bearing while you are in there, since the added cost is not too bad and it might save you having to break in there again in the near future.
Otherwise, I would wait till you get em done and see if traction becomes an issue.
the car only has 77k miles and my rear end feels nice and strong...no one wheel peel here...what bearing inside the diff are you talking about....how about some 31 splines? you guys think their worth it?
31 spline axels will be more important once you get your h/c/i installed. Right now it won't really matter much. But, of course, it's always easier and cheaper to take care of that now rather than do both in two separate steps. One reason to think about doing it all together is the ABS sensors. They get bound in pretty quick, and have to be smashed out if you ever need to pull the axels. That runs another $100 for replacement sensonrs.
At 77k miles, your bearings are probably in decent shape. Maybe you could look at it this way (especially if the h/c/i isn't happening for quite a while). Do the gears along for now. Then when you do the h/c/i, or shortly thereafter, do the 31 splines and rebuild the rear end with all new bearings.
BTW, the bearings that I was talking about are the 2 carrier bearings, and the inner and outer pinion bearing. Also, you can do the rear wheel bearings at the same time.
Do the bearings now. My rear was quiet so I tried to stay on the cheap... now my car is in the shop for new bearings just 1000 miles after the gears went in....
You wont need to get 31 spline axles until you start getting in the high level horse power and some slicks. With the mods that you have you would just be wasting you money. I make 340 rwhp and i still am using stock axles. Invest that money in some other mods. Like buy some drag radials. Those would be your best investment