1.) The recommended octane for this vehicle is 91. Many gasoline manufacturers these days use ethanol in there gasolines as an antifreeze and octane booster. Are there any problems in using ethanol blended gasolines in this engine?
Possibly. See section 9-4 of the 2002 Owners Manual here (page 229):
Online PDF version, pretty cool eh?
2.) The automatic version of this vehicle is rated at 246 lb-ft of torque and the manual at 231. Where did the other 15 lb-ft go and can I get it back?
It's the torque converter in the automatic transmission, not the engine output.
3.) I was hoping to run synthetic motor oil in the vehicle. When should I make the switch, should I make the switch and after how many kilometers should I do my first oil change? The recommended number is every 6000 km but I figured I would do my first one at 2000-3000 km still putting in regular oil and then at 6000 km do it again and switch to synthetic. Let me know.
Change the oil at 1500 km to get rid of the break-in bits, use regular oil. Switch to synthetic at 10000 km after the engine has had a decent break-in. There is endless debate on when to switch, but a couple of extra oil changes with regular oil instead of switching at the first change won't "hurt" but I'd be skeptical of switching right away without the break-in.
4.) Does anyone have numbers for increases on the new exhaust replacements from Calmini or others?
Nothing definitive. I think the only numbers so far are from an HKS install, and they weren't comprehensive.
5.) What is the maximum carrying capacity (lbs.) of the X and if I get leaf spring helpers can I increase this and by how much?
Max Gross vehicle weight (on my 2000) is 5200 lbs. Max 2740 lbs. on the front axle, and max 2850 lbs. on the rear. Just what are you planning to haul in/on your X that you are concerned about exceeding this?
Can't say how/if you can increase the max load safely.
6.) With the S/C is there any benefit to switching to the K&N filter?
Yes, the K&N doesn't discriminate.
7.) I am getting a brush guard for the front and do plan to go offroading, what offroading X-tras should I put on when I get it? Torsion bars etc. or just wait and see. The new fuel tank and axel skid plates on Xterraparts.com look great does anybody know anything?
Take the brush guard off the day you get the X and put it up for sale on Ebay.
8.) How many offroad and performance upgrades can I do before I void my warranty?
Depends. You may void portions of your warranty depending on which modifications you add. It's rather subjective too.
9.) Does anyone have any experience with the Explorer 2 tent advertised on Xterraparts.com?
Save your $, you can sleep in the X as it is.
Brent