This is hoy my YJ looked with 31's and a 4" lift, so you can expect yours to look something along these lines...
Also, I used to run 31's and 4.10 gears on the 2.5 with the manual tranny; it's not great, but it is driveable. Just forget 5th if you are driving against the wind or if there is any kind of upward inclination on the road (even overpases) when driving at highway speeds. After the pic was taken, I changed gears to 4.88 and kept the 31's, and it was AWESOME! Then I moved to 33's, and I lost a lot of driveability at highway speeds (once again, I have to downshift to 4th if there is a head wind at highway speeds); I sure wish I could go to 5.13 without having to change both axles!
This is the now picture, for your reference as to how much the tire spacing will make... (of course, more than just the tires have changed, but you get the idea!)
i would consider trying a bfg all terrain in 33X9.5-15 if i couldnt regear with 4 inch lift.
BFG ats do a great job as a daily driver on the street and is still very capable offroad with the exception of deep sticky mud, and the narrow width of this size tire has MUCH less rolling resistance than the size you are now running so it be much easier for the 4 banger with stock gearing.
This might be worth a try; the AT is lighter than the MT, and the width will cut weight AND wind resistance...
Learn to shift at the right time - get the revs up near 4000 and leave them there. There is no reason why a 2.5L with 33" tires can't go at highway speeds.
Mine still has 4.10 gears and 35's, works fine up to 70 mph. Too many times people think that they are supposed to be running at 1500 RPM on the highway, it's a 4 cyl - wind it up.
While I dont agree that 35's and 4.10 would be advisable for the 2.5L, I do agree that the little engine is quite happy to maintain high RPM's; you can drive that little sucker at 3,000 RPM's all day long and it will not quit!
Hope this helps!
Felipe