What kind of performance increase did you notice (if any) with those mods?

Not much really. I always felt sort of a flat spot between about 2700 and 3000 RPM in my jeep where the engine would rev higher but it did not feel like I was going any faster. I have only had the air tube for a day, but is seems like it has cured that flat spot and I get smoother acceleration through that range. Now technically I don't think that such a flat spot should be possible, but that is how it has always felt.

About how much did it run you? Since I smacked my 33x12.5 tires on it, I'm trying to scrounge together any performance increase that I can find.

The tube was about $70 and the filter was $40. But, I would recommend just getting the tube and then finding a K&N filter that will fit it because the filter they sell feels kind of cheep. Anyway, all of these mods are not really going to offset the larger tires. It sounds like it is time to go to 4.33 pinion gears. Remember what JEEP stands for (Just Empty Every Pocket).

-Mike