SawTroll

The power to weight (and cc) ratio is very low though, as on most Echo saws. The exceptions are the 620 (that is OK regarding power, but not top class, and not light enough) and the 501 (that is light, but still lacking a bit on power, compared to true 50cc pro saws).

Yes, I agree.

The best "milling Stihl" among current models is of course the MS880, but that doesn't mean it is the best one ever.

No, it was a "homeowner" class saw, with plastic case and "clamshell" engine.

Those belong to an older Partner designed saw family (the P400 family).

The top end and the performance is very different as is - but any 346xp top end is a straight bolt-on for the 2149.

The 2145 is the same saw as the Husky 345, with the usual Jonsered to Husky differences. In the late 1990s Husky introduced two rather similar looking "saw families" that even shared some parts, but had some very important quality differences. The 345/2145 belongs to a family of "homeowner" saws with a plastic crankcase, a "clamshell" engine and "open port" cylinders - typical features for "homeowner" class saws. They proved to be very good saws for that classification though. This family consisted of the 350/2150, 345/2145 and 340/2141. Even though the 350/2150 basically was a clamshell design, the traditional clamshell top end was replaced by a metal upper case that was not part of the real top end, but worked as an upper bearing cage and a base for a "non-clamshell" top end. This is important if you want to upgrade the performance of any of these models. The other "saw family" was the pro grade 346xp family, with a vertically split magnesium case and some added "pro grade" features. Trough the years this family consisted of the 45cc 346xp/2147, 351/2149, 353/2152 and NE (50cc) 346xp/2153. The top end were closed port quads, except on most of the 351/2149s, that shared the open port top end with the 350/2150. The 351/2149 and 353/2152 were "semi-pro" saws, that deliberately had top ends with less performance than the true pro saws. Using the "bearing cap/cylinder" base of the 350 and a few simple tricks makes it possible to use the strongest top ends (NE346xp) on all the mentioned plastic cased saws, in addition to all the mag cased ones.

The answer to the weight question depends on the exact model from each brand - far from all Cannon bars are particularly heavy. As I see it, the Chinese noses used on most Cannon bars are a major disadvantage - and they look crappy. I don't really understand why they can do a thing like that, nobody buys Cannon bars because they are cheap anyway (they aren't, even with those noses)...

Total bars are "rebranded" Tsumura bars, when the topic is high end RSN bars.

Provided your bar is .058 (1.5 mm), Oregon 21LPX or Stihl 25RS (chisel chain). I prefer LPX over RS by a slight margin. If you some times cut "dirty" wood, keep some BPX or RM (semi-chisel) as backup.

The best of the Emak brands (Efco and Oleomac) saws were the 62cc ones, that were discontinued for emission reasons some years ago. What they all share is that they are plain UGLY, aesthically extremely badly designed - and have bad AV + fit & finish. There may be newer models that I don't know about (I know about some), and what I see doesn't look good at all....

Yes, but they "happen to" cut a narrow kerf (narrower than regular 3/8") as well. As the "chassis" of those chains are lower and differently shaped as well as the cutters, they don't really fit on regular 3/8" drive sprockets, and the nose sprocket of regular 3/8" bars are incompatible with them (usually doesn't work at all). This is a challenge on the 550xp etc - but it can be done with using a standard 7-pline drum from/for the 562xp and the standard spline picco/lo-pro rims from GB (Stihl ones only come with the Stihl only "mini" 7-spline, and are no-go on those saws, or anything else but Stihl). Regular 3/8" drive sprockets are too small, and about like running the chain on a sprocket that has been worn well past its useful "life" - but sort of works if you can live with the chatter and accellerated wear. Then there is the question of why anyone will want to do it at all.....

Looks like the only parts that are available separately are the springs. 560 IPL 2016-08.pdf

The xt versions have a carb with a larger venturi than the older versions, hopefully the intake is wider as well, to compensate for the divider?

I am not an expert, but would assume it is best to tune it right, regardless where that is in relation to the listed max rpm?

Very close to, at least.

The max power specs usually are surprisingly close when they are tested by a major test facility on a certified dyno, at least from the major brands - seldom more than .1 kw off, and usually spot on (with one decimal). That said, the max power (and max torque) numbers are of course just a snapshot of one point of the power curve trough the rpm each, so they aren't the full story.

As expected from you - but it doesn't change the facts.

The rated power is on about the same level as most fairly recent 90cc saws, and this is a much larger and heavier saw. Less than 7 hp from 116cc is extremely low.

Good question, I'm far from sure that change will be an "upgrade" on a saw that weak. It might in some conditions though?

....or this, if the saw isn't an X-torq, but one of the original ones: WS manual 2000_372 365 362.pdf

Yes, and I also wonder what sort of crankcase he would get for that price. If it is an aftermarket it really should be avoided - and if it is a used one it usually is a gamble. This may help: WS manual 372 365 X TORQ 2013-05.pdf

I believe that is good advice - I don't see any issue if that is done. An 8-pin is another good idea.

What is "best" depends on a few factors regarding the wood and cutting conditions, and some times the operator as well. As my wood and conditions usually are "clean", I prefer chisel chain (not semi-chisel), and my favorites are Oregon LP/LPX, Oregon LGX and Stihl RSC/RS.