B&W 802 D2 Capacitors Worth Upgrading?

Here are a couple of novice tips from another novice.

Capacitors have a direction, in/out. They have a label on them to tell you what end. goes where. If you install them in the wrong direction they may blow up. I had a friend had one go off in his face. That’s when he quit electronics.

Do not use flux!!!!  

Buy a quality iron that gets hot enough. It needs to be hot so that it will melt the solder on the board without getting the capacitor and surrounding components overheated.
I highly recommend that you go on eBay and buy a $15 amplifier/speaker kit for practice soldering.  Learn how to sweat a capacitor out of the board after you’ve installed it on your practice kit. (You Tube) You will need that skill to remove a cap from the crossover board without destroying adjacent components. Not as easy as it sounds. 
 

Bent

 

Speaker capacitors are non-polarized, and using a polarized cap in a crossover is a Very Bad Thing. The best speaker caps are Metallized Polypropylene (MPP) because of their lower losses and self-healing capabilities. All Polypropylene (APP) caps have longer life but higher losses and are typically found in power supply use. Non-polarized Electrolytic capacitors are less expensive, but dry out and drift off value with age. Those are found in less expensive speakers. Newer NPE designs have improved a lot over what you'd find in a 40 year-old Advent. Back in the day, upgrading the high pass or piggybacking the low-pass caps in Advents was a common tweak with noticeable refinements in the midrange and high-end. 

Yes, thanks @erik_squires and all for all the purely informative feedback. Despite the inevitable few who sour the tone, I’ve always found Audiogon to be a place to exchange information and experiences. While I have great relationships with sales staff at my local dealers, I find I rarely get good good info from them. And sometimes their advice is downright terrible! I always find that once I sense there is a consensus on these boards, it’s usually worth paying attention. I never would have thought to audition the Diablo 300 amp, if not for these boards, and I absolutely love my amp!  I try to do my best to share my experiences as well.

 I have a pair of 30 year old Klipsch Forte speakers.  I put all new caps in the crossovers and it woke them up.  Nothing fancy just new manufacture name brand caps.  So I think there is benefit in replacing caps that old but to the OP I don't think your speakers are old enough to warrant replacing the caps.