Given the propensity of the Mk I swingarms to crack, I'd give it a very careful look over/under/around and fix it so you can ride it for a bit before going the whole hog with XT/XTR..
At least that way if you take it on a 'normal' route, (i.e you're not 'abusing' it) and it cracks in a couple of weeks or so, you know you need to replace the swingarm, and you havent spend money/time on tarting it up - yet
Check under the swingarm lower brace, just above the Pivot - that's a common crack location (arf arf..)
If it lasts the course, so to speak, then XT sounds nice!
Yup, there's some argument over 'original' MV equipment, safe to say that some were sold with White Industries stamped Sugino-made cranks and some with Sugino-branded Sugino-made cranks..
Mine had Whites, but unfortunately 170mm and 94 BCD, so too short and a pain in the ass to get decent rings for!
They aren't heavy, but don't get suckered into thinking that they are 'boutique' and go paying £40-50 for a set either, like I have seen some advertised for (!)..
2013 On One Scandal | 2011 Ghost ASX 3700 | 2008 Magura Test Bike | 2006 Raleigh RS950
1999 Voodoo Hoodoo | 1999 Raleigh RSP 450 | 1997 Giant ATX-D 990 | 1997 Ghost X-700
1995 Giant Cadex MCM-3 | 1995 Voss Ti | 1993 Giant Cadex CFM-2 | 1992 RS Topline Mammoth