98s are not the panacea year you think. 99s and 2000s drive a lot smoother. Yes they have a couple of failure issues but if these parts have been recently replaced you usually don't need to worry about it for a while.
Personally, I think that you would be MUCH happier in a 2005-2007 P2 wagon, be it FWD or AWD (XC70) and can be bought privately for 5-6K with halfway decent miles, (under 130K).
The work needed on some is not different than a 98-2000 but they have a MUCH nicer ride a MUCH better engine (the 2.5T) and are much less prone to squeaks and rattles.
I paid under 6K for the V70 (2.5 TURBO, picture below), a rust free top and underside from FL).
I did the usual work needed at 100K miles, did a few mods and I have to tell you that this has been one of the most trouble free Volvos I have had...and I have had a LOT OF THEM, personally and the ones I sell.
This is not a sales pitch but look at my black 2006 XC70 in the classifieds. Yes, it's more than you want to spend now but ALL the necessary work and then some has been recently completed by me. You should be able to buy these for 5500 to 7K. Yes, most will need the work I listed that I just completed but most of it can be done over the next year or so if you buy one of these.
Find a nice one to try it out first and before you go backwards.
I'm older then you so listen to your elders!
My current personal 2007 (107,000 miles)

2006 XC70 AWD that's for sale (105,000 miles) Ad in the classified sectios







