I've owned a PC557 version 3 for over 5 years and it is an excellent tool with one exception. When using the dust bag, the tool is prone to sawdust clogging the dust port.
Frustrated by having to use a coat hanger wire to unclog the machine every 4 cuts, I came up with a modification that has eliminated this problem for me.
All you need is Rockler item #42251 ($7.00) and an 8" plastic wire tie.
Discard the removable tube that normally connects the dust port to the bag. Cut off the small first step on the Rockler #42251 hose adapter. The new opening now matches the diameter of the dust port. Unzip the dust bag. Insert the hose adapter into the bag with the small end protruding from the spring clip opening. Loop the wire tie behind the spring clamp and tighten. Attach the protruding end of the Rockler adapter to the dust port.
Using this fix, I have gone from 4 cuts and a clog to 20 cuts and no clogs on pine, popular, and red oak.