Don't take this the wrong way, please..... and you'll probably still get some good info out of this site.
This is the North American XJ Association website. You've got a YJ I think(if it has leaf springs; TJs have coils) which is not what this crowd is particularly expert on.
Personally, what I'd recommend is getting some skid protection, and get together with a local club so that you've got a better idea of what your Wrangler can do. Wheel it a little in (relatively) stock form so you do know if & how your mods are working.
What you've asked about is more than a few bucks, and as you say, you really don't want to screw it up.
More specifics....... auto/stick? 4cyl/6cyl? Any mods on it now? What rear axle do you have (D35C or D44?) Are you planning on keeping it as a daily driver, or will it turn into a dedicated trail vehicle? What part of the country are you located in? What kind of offroading are you planning on, i.e. mud, rocks, etc.?
If you're going up to 37s, you probably don't want to sink anything into a D35C (my opinion only.) The front D30 can be helped. Gears? You're going low...... far lower than what I think about, I'm stopping at 33s on my XJ. Tcase gears? Stock NP231 is 2.72:1 but you can get a 4:1 gear set.
Don't forget a Slip Yoke Eliminator kit and a new rear driveshaft. That teeny tiny little Wrangler driveshaft won't take much lift before it'll shake you loose from your back teeth.
ChiXJeff
