help with rear end gears

[syntax_erorr]

alright guys I gona change my rear end gear and I wana know what you guys think I should put back there...I wana go with either a 3.73 or 4.10...right now its stock(3.23I think?-don't know becuase numbers in glove are messed up)
anyway my car as of right now revs @ 2,000rpm in 4th gear with od on at 70Mph.....what I'm wondering is: A. anyone know how I can find out what it will rev @ 70mph with a 3.73 or 4.10 in it? B. right now my car does 0-60 in 8.43 sec and a 1/4m of 16.32 @ 82.6mph...anyone have a rough idea of the improvements in 0-60 and 1/4 time with a 3.73 or 4.10?the car is also an auto in case you were wondering

[ September 11, 2003: Message edited by: syntax_erorr ]</p>

[syntax_erorr]

anyone?

[AlienInv8r]

Most autos without Y87 come with 3.08 gears, but there's always those few oddballs that could get different ones. Chances are that you have 3.08s though if you're a plain old A4. When people jump to 3.42s, they can generally drop off .5 seconds from their ET. I'd guess slightly higher with 3.73s, maybe .6-.7?? All depends on the driver really. I asked one A4 guy a few weeks ago that had 4.10s and he said he does 70mph@3000 rpms or so. You do have overdrive and all, but I think with extended highway trips that that may be a little extra wear on the engine. If it's a city driver though, you could probably pull it off fine.
Personally, I am going to go with 3.73s, and hopefully with my next paycheck too. I think that'll keep decent rpm ranges for the engine, yet still provide a lot of pull with it. I've heard 3.73s do roughly 2500pms@70mph. Also, dont forget about needing to get the speedo recalibrated, otherwise it's gonna be off by like 15% or something. Shiftpoints will also be different, and your car will short shift. Hypertech can fix that if available for you car, if you're like me, '98, you'll hafta get custom programming to fix shift points, which sucks since I'm gonna hold off on that till I get some major mods done. But you should still be able to drive just fine, and even unprogrammed, they will make you plenty faster than regular 3.08s will by pulling faster throughout each gear.