The first two photos show the piston. the one on the left hand side is the one that goes with the kit I bought a few years back and shows that the transfer has been elongated. The one on the right is the one just back from the tuners who has smoothed the transfers.

And this is the other side of the pistons

Th barrel on the RH side is the one that I have just got back. The change to this barrel is to smooth the ports and adjust the exhaust port. So for this new tweak, the top of the exuast port is 32mm from the top of the cylinder and 56.5 to the bottom and is 46mm wide. As for the older barrel, the measurements are 32,55 and 41mm wide. In addition, the older barrel has the initials TWS

As for the other barrel ports, they all look similar in size, but with the exception of the old barrel. Here they have crudely drilled out a blanked transfer port.

Your thoughts would be appreciated, as I have a Rally 200 engine that may like the older barrel and piston, provided that the extent of tuning has not been bodged.