New (to me) Stihl 028 wb

Just picked up a used Stihl 028 from a guy who is a Stihl service technician. Saw is in great shape, and came with an 18" bar with 2 chains and a 20" bar with one chain.

I have a couple of questions for those more knowledgeable with these saws than I;

-What is the largest bar that would make sense running on this saw? Even if I could put a larger bar on, would it really make sense? My thought is to just get a few more chains for the bars that I already have. However, on a rare occasion I would need to cut some bigger logs. I have passed up trees that were down but I thought were larger than I had saw for (before this my only saw was an MS 250)

-I read that it is possible to upgrade an older Stihl with the Quickstop system. Has anyone done this? This seems like a good idea, but I thought I would check to see if anyone has done it and what their opinions on the subject might be.

Thanks for the replies.

My plan was to get a second saw and probably run the 20" bar on the 028 wb and maybe a 16" on the MS 250. Just having a second saw readily available will be nice.

Maybe someday I'll get an even bigger saw. However, my wife already commented, "You already have one saw. Why do you need a second one?"

I think I'll probably operate saws like my pistols. My pistols are all black, so an extra one in the gun safe goes unnoticed. If my saws are all orange...