I bought my 2000 V10 XLT back in July for $7500. Had a lift, 35in BFGs, and only 75k. Sits pretty tall, is difficult to climb in/get out, and rides really rough. Can't wait to swap out the old lift and get it back to a more reasonable height. I found a stock pitman arm, drop bracket and W-code front springs. Have already removed a leaf from the rear and will toss the 5.5in block when it warms up. For anyone considering one of these rigs, try to find one with the 4.30 gearing. All of the PSDs came with 3.73 and so did the vast majority of the the V10s. Bigger tires just kills the towing ability of these and I like my V10 to rev a little more than it currently does. I tach at 2000rpm @ 75mph, but would like to be between 22-2400rpm at that speed (better MPGs and better for towing).
So far, the mods I've done are very basic. I added a dual-12v/USB charge port under the dash that is switched. All of the 12v ports on these (4 stock) are live all the time, so its nice to be able to shut down something and not kill a battery. As an example, I kept the stock stereo and added a bluetooth adapter to this switched charge port. Don't want to have to put it away whenever we exit the vehicle, so I just switch it off. Also, aftermarket stereos disable the rear seat controls of the factory system, so keep that in mind if you are planning an upgrade. I wanted my kids to still have control of the radio on road trips and it still sounds good. The most important repair that I've done so far was to install a new windshield. The factory glass was perfect, but the seal was not. Rain water had been leaking in for some time and drips right onto the fuse panel/GEM under the dash. This is a VERY common problem and replacements are not available. After a storm, my radio would short out whenever I flashed the hi beams. It also caused a massive parasitic drain on the battery resulting in no-starts in <6hrs. Got a replacement installed (mine cracked on removal) with a new seal and lifetime warranty for <$150 from Safelite. 1999-2002 models were rated to tow up to 10k lbs and the 2003-05 models were rated to 12k lbs all because of different size hitch/frame bolts. Upgrade to the beefier bolts if towing higher loads. I run a ScanGauge II to monitor all the sensors under the hood. Programmed the SCII with the proper X-code and I can view transmission temps. The 4R100 in the early 7.3PSD and all V10s use a smaller cooler, so an easy upgrade is the cooler from the 6.0 rigs. I haven't had trans temp issues yet, but my toyhauler is relatively light at <6k lbs fully loaded. For now, the smaller cooler stays. Some of the early V10 models also suffered from a choked up Y-pipe. A simple swap from Ebay and other venders gives better breathing and a slight bump in power. Its a goofy setup, so if you want a good laugh, Google it. Here's my rig from our most recent camping trip: