There is some debate on the 82 cc saws but my impression is PM850 is the most powerful, followed closely by the SP81E, SP81, and SP80 and CP80DX.
The PM800/805 seem to be less impressive but it could be the extra muffler just makes them seem more tame. The PM850 Super is just the PM800, the PM8200 is totally different design but right in there with the PM800. My DE80 is lagging behind the other 82cc saws but it has the most wear of the all.
All of those models use the same anti-vibe system with some difference in the lower brace. Others with the same anti-vibe would be PM570, SP60, and SP70. The CP55 and CP70 also used the same front & rear anti-vibe mounts but had a different arrangement on the bottom.
It is certainly worth putting some time & effort into making the 81 a runner.
Mark