'04 TJ Engine break in question

\'04 TJ Engine break in question

I am the new owner of a 2004 TJ X model. This being my frist brand new Jeep (all the others had at least 90k on them!) I was wondering if I should be doing anything special for the break in period. The owner's manual says the first 300 miles to keep the high RPM's to a minimum, but I've got 850 miles in it now and for some reason, it just doesn't seem to have the power in 5th gear to maintain speed up slight upgrades. I'm sure my gears have a little to do with that, but I was wondering if anyone else has picked up some power farther along into the early life of the engine. I also just slapped 31's on it so, the crappy 215/R75/15's that came on it might have let me maintain speed better also.

oh boy do I have lot's to do to it!