I have tired reading though this section but there is no clear information, most posts are 2+ years old, mostly about blown up Kawi pistons.

Having just finished my "stock" R5K restoration I want to move on to something more custom starting with an identical R5K I scavenged for spares. Got enough to build it back up but engine needs service:
crank will be shipped off to Andy for repairs any day now but both barrels have cracks on the exhaust bridges, I expect by the time they are welded, plated and adding cost of new pistons, rings, gaskets, seals... total expense will be approaching the cost of 300 kit.

Any downsides to doing 300 conversion at this point?

This is for a street bike but not for daily use, just to have fun on weekends as I use LC4 Austrian Tractor for daily commute