I have a 2011 sport, 6 speed, 3.21, with 32's. I am going to put a 2.5 lift on it with 33's and not regear. Iam no speed demon, a little slow on the take off, but than again I am not in a hurry to get anywhere. I am just saying.

 

I also think it depends on 2 dr. Vs. 4dr. And what brand tires. I have a 2011 JKU with 3:21 and after putting a 2inch lift and 33 inch trail grapplers on which as you know are very heavy and wide and measure 33 1/2 my jeep driving performance went very noticeably downhill. 6th gear is useless 5th gear is almost unusable too and at 70 mph in fifth gear, I have no pedal left and am turning only 2000 rpms or so but cant really accelerate into much higher rpm range unless i downshift into 4th. I get about 12.6 -13 in town and 15.6 highway. I have done numerous "performance" mods to no avail. I will at some point re-gear. The way I look at it is I've spent thousands on mods over time so whats a bit more to get more acceptable drivability back, more torque and power in the lower gear ranges, better offroad performance etc. The hard part for me is feeling comfortable with a shop to do it right and not ruin my new gears. There aren't that many experienced shops in my area and I hate to drop that much loot and maybe have issues.

 

Ok, I get your point guys, what I'm missing the most here is overpass confidence on the highway but I'm no speed demon either, it's just that when trying to overpass going uphill (as an example) I feel the loss in power makes it a little bit more risky on this small mountain roads I use to drive daily and that are populated with trucks going really slow.

@Theterminator
You mentioned that I will get higher RPM's with lower gears, that's something I understand but is that the main factor that will make my mpg's go worse?

-edit (it also has been brought to my attention that bigger tires should lower my rpm's! is this true?)

Putting this another way.. if I don't change gears how worse should I expect mpg's to be just from swapping my old 29's for 33's? (can't measure by myself as I didn't recalibrate my computer yet)



-edit
new question: if I go from 29's to 33's and swap gears from 3.21's to something like 4.10's would I stay on the same performance curve and mpg's?

 

as per what TJM says this is my actual setup.
-2 door JK sport
-6 speed manual transmission
-3.21 gears
-Mickey Thompson Baja MTZ 33's (285/75/r16)
-Spidertrax 1.5" spacers

 

just bought some 33's yesterday. havent put them on yet. my stock wheels are 29 inchers.