The X is very capeable. However the hitches on the 00 and 01 I think are only rated to 10k lbs. the 02 and up were rated to 12,500 lbs. the only difference is the mounting hardware on the later ones are larger to carry more weight. Swapping out the hardware will get you the higher rating on the hitch.
An 8000lb dry trailer will weigh approx 9500lbs loaded for a trip. I can tell you from experience the v-10 with 3.73's towing 9500lbs will not be fun. It will do it, but it will struggle and you won't be in the powerband for best performance. I went from 3.73 and it was a night and day difference!
My trailer is 7100 lbs empty and 9200 loaded for a trip. The X likes 4.30 gears to tow anything over 8k lbs and it needs 4.30's for anything near 9 k lbs and over!
A lot of people modify the rear suspension to tow heavy! Some install SD truck springs some use air bags. I use air bags and I installed a Hellwig rear away bar (my X didn't have a bar from the factory!). The X can be finicky to tow with, but when set up properly is one of the best HD SUV's to tow with. And a tuner from 5star tuning will give even better performance out of the V-10.
You'll also want a good hitch. I use and highly recommend the Reese Straight Line (Dual Cam). I have towed up to 12 hours straight and it's comfortable the entire time!
Any other questions just ask!