Haven't posted here for awhile; saw this thread and thought I'd offer my 2 cents. The '02 abs just rolled over 99,000, and runs better than it ever has....
Just got back from a 5k+ trip on the new XMs. Like them a lot. Construction much heavier, and seem to be holding up waaay better than the old Storm2s. Front, 120/70, took almost nothin' to balance, but the rear, 160/70, quite a bit. Slimed 'em, because I lived in fear of having to pull the rear wheel off on the road, as it presently has a trailer hitch.
Rims must be squeaky clean for tires to bead accurately. Failure to clean can also contribute to imbalance due to inaccurate "setting" on the rim. Shops won't do this due to flat-rate. The wrench makes the same amount per tire swap (at least that's how it worked last time I turned wrenches for $) and cleaning takes time he wouldn't be compensated for. Been using cooking oil for mounting lubricant for years. It works reeeaaally well.
I'm approx. 230lbs of solid beer-disposal unit, my wife pretty close. Had full soft bags and some gear on the rack and pulled a Uni-go trailer. Twisty roads solo from Colorado to Texas to Florida, picked up Laura in Orlando, then twisties back to Colorado. 65-ish mostly, 300-500 miles of 80 to 90 (any faster, and the Uni-go would frantically begin getting my attention...) 42lbs front and back, gauged every three days, kicked every morning in between. Rear wearing a little unevenly; plainly, the rear doesn't like this much weight, but again, MUCH better than the old Storm2.
Worked good in the dry, good in the wet, although I didn't ride what I consider fast. Typical Avon head-shake below 40-50 mph. Irksome but tolerable.
2 lbs loss per week? That's a leak. Check the tread carefully for a nail or some such. Small punctures can be fixed but only with high-quality patches internally.
Next, break out a spray bottle of soapy water and start chasing. I'd look at the stem first (just 'cause it's easiest); pull the cap and gently put a wetted finger tip on the top of the valve. If a bubble grows between yer finger and the valve, there's yer leak. Next, push the valve around a little and look for cracks in the base. Spray it with the soapy water. Look for bubbles. Check the beads next (easiest if the wheel's lying flat) and be patient. Rim leaks are harder to spot.
A 1000ft change of elevation is good for about a 1 lb change in tire pressure (42 lbs base pressure), give or take. If you start in Colorado, 5,000 feet and 42 lbs pressure, and end up in central Texas, you'll find 37-38 lbs in yer tires. Just sitting in direct sun is good for about a 2 lb. increase from a cool overnight. Pencil gauges are OK, but ONLY if you cross-check the accuracy against a known good digital gauge.
BTW: Slime, the company, makes a nifty little "tire top-off" 12v compressor perfect for traveling. Tiny thing, and cheap. $10 at Mal-wart.