The XS filters aren't really filters at all, rather, they are strainers, so some smaller particles will still get through. And of course, the sump filter is known to self destruct, so I'd be looking at that area first, either a guard over the section at risk or an after market unit.
Heiden's sump filter looks good, if you are going to filter properly it really should be before the pump. Having said that, I use a spin on filter after the pump. I also run a cooler, inlet and outlet facing up, so very little drains when parked, but it was a lot of work making and fitting and modifying.
Air cooled engines don't like idling or running for longish periods when standing, they rely on the movement of air, For that matter, they don't particularly like high revs for longish periods either or particularly hot climates. I had Triumph with a cooler and Norton spin on filter when I was stationed in the tropics, it still tended to overheat.
If you are going to add a cooler, do it properly, add a radiator style cooler.
My system is all home build, but it works good and looks good.
Of course, most XS650s don't have any of this sort of trickery and have been going for 50 + years with no problems, it really just depends on your outlook and how far you want to go and how much you want to spend, either time or money.
