The only visible difference between the two is that the lower transfer opening is different and the MS200T cylinder has a split transfer which, I believe was to reduce the stacking effect within the transfers and effectively allows both front and rear transfers, to act independently.
In reality, the OEM kits give 200psi when new and the gasket is deleted. If you try a saw with a worn OEM or aftermarket 145psi cylinder and then try one with 200psi you immediately notice a much faster spool up time and the immediate attack on the wood is far more urgent. Compare a MS201 to a MS200T and you really see that the MS200T just has that immediate torque in the wood. Anyone that has tried to do timed cuts with these two machines will have found the MS201s need a light initial feed in to get it up to full tilt or it will bog....the MS200T is so nice because it pulls hard from low revs.
I was in the position of choosing the Meteor or OEM kit. I get a bit of business discount from L&S so it made the OEM choice the best one for me.
The Meteor pistons are the best ones after OEM, they use Caber rings and are proper. I strongly believe their cylinders are Hyway ones, some say they are finished by Meteor...I can't say but my mantra has always been to retain the OEM cylinder whenever possible rather than using other AM options.
So...in regards to your situation....my stance would be to...inspect each cylinder and only replace if the cylinder is scored through a circlip coming lose or if the Nikasil plating has come off - usually around the inlet port through not cleaning the air filter.
A bit of seize transfer can be removed and would lightly hone the cylinder above the exhaust port as the open transfers make going lower more difficult, and then fit a Meteor piston with OEM circlips just to be sure....they are the best.