Should I upgrade my Advent 5002 speakers?

Mr. Bourne is correct. I’d add that anything you buy is going to sound very different then the Advents, which were very good speakers, but age has definitely change their sound over the years and you’ve adjusted to them. I’m betting you’ll find most speakers will sound ‘bright’ to you. You’re best bet is try and listen to a number of speakers, and don’t mistake clean and clear for ‘bright’. The luxman amps are great. 

I think my dad may have a pair of these, I only know them as "Large Advents".  When I was home last I was impressed with their sound even though they are connected to less than ideal electronics.  You can always pick up a second pair of speakers, but think that the Advents are worth keeping.

You might try rebuilding the crossovers first , if you look up images of the 5002 you'll see that they are a simple design so upgrading the resistor , replacing and upgrading the 2 old worn out electrolytic capacitors ( electrolytics degrade over time and those are very old ) should make the speakers sound better than ever !   So for under $30.00 per speaker you can love your speakers even more .

Should have mentioned that the crossovers have been rebuilt already, but always good advice for older speakers.

@jasonbourne52 I really do like the Advents, but guess I’m just wondering if they’re a weak link in my system.  My listening is mostly jazz and rock, with a little classical thrown in from time to time.  Bass is only important in so far as the can accurately reproduce it, but I don’t want it thumping when it shouldn’t be.  I’d like to keep the size pretty close to the Advents and the price under $4000.  I’m more concerned with accurate than loud.  The MoFi speakers seem to fill both of those desires, but they’re still pretty new so there’s not a ton of info on them yet but what there is is glowing.