I have an XL-2 I bought new in 1988.
It's the one bass in my collection that I will never sell. The tone is amazing -- not overly bright like a Modulus, but articulate and clean, with loads of booty. It's a very versatile bass that does most everything well except for slap (narrow spacing). Dial back the tone knob and you can get a fabuolus dub tone.
Even though I mostly play 5ers these days, I still play it about 1/3 of the time, because it plays so well and sounds so great. I just can't seem to put it away for long. It's the only bass I've ever owned that required no maintenance, and almost nothing in the way of setup. Except for two small dings on the back of the neck, and some minor wear, it is in the same condition as when I bought it, despite being my main bass for over 15 years. XLs also make great travel basses. No real worries about damage, and all you need is a good headphone amp for practicing.
The XL-25 "narrow 5" strings must have incredibly narrow spacing. IIRC, the neck and body are the same, so putting 5 strings on that neck and body must make it incredibly tight -- I like narrow spacing, but the spacing on my XL-2 is narrower than any of my 5-strings, and about as narrow as I could stand. Plays really fast, though.
You can pretty much forget about ever finding the "wide 5" XL-5W model. Fewer than 70 total were ever made, in all combinations. Last one I saw sold for $4500 from a dealer with a really bad reputation.