I wonder why there are no aftermarket 80 or 81 mm Nicasil cylinders. That would bring that part of the XS into at least 80's/ 90's standards. Nicasil is extremely wear resistant, and having no iron/ steel liner improves cooling. And you even save a little bit of weight as well. I pulled the cylinders on my 95 Ducati 600 at around 60 000 km/ 40 000 miles, to install a big bore kit. There were absolutely no wear lip near TDC, and the honing crosshatching was still very visible. These late 80's and onwards aircooled Ducatis have the rear head exhaust port facing aft, just like a Harley, so the cooling is not really optimal. But still no problem.
I have also been messing a bit with a 98 Suzuki 125, which has a traditional liner, and several big bore options up to 170 cc are available. I ended up with the budget option of a 61 mm/ 143 cc Wiseco piston. Only to discover later that Athena offer a 155 cc Nicasil cylinder kit. Which I definitely would have got if I knew.