It seems to me more likely than not that, back in the day, if someone had been going to spend real money on upgrading a WS, it would have been on the best of them. The best of them were the last of them: the models with the 14" screen, and the (common) 266MHz or (rare) 300MHz processors with 1MB L2 backside cache. Some of the earlier WS series were rather poor (12" passive matrix screens that were truly dire and that at 800x600 only, or 13" active-matrix screens that were highly unreliable, and some even had anemic, cacheless processors), so that you'd have been nuts to want to invest any more money in one. You couldn't even swap the screens between good and bad models, mostly. But they got much, much better. There is a reason that it is the last iterations of the WS that you mostly see for sale, as those are the ones that most pleased, were most reliable, and thus that most often have been valued and have survived.
Frankly, though, I would not fuss over a Sonnet upgrade for a minute. A 266MHz WS is already a slick, genuinely "old world" PowerBook for OS 8.1-9.22 work, and it will even run X.3 relatively well if you have the RAM for it (X.3 via xpostfacto). I would judge it to make much more sense to spend the money on a Pismo if greater speed in OS9 or if OSX on a classic 'book is desired. Unless you are doing something crazy like encoding mp3s on the WS, you will not really want for more megahertz. Most everything is perfectly snappy already.
I used a 14" WS, 266MHz, daily for several years in OS9 and it never really disappointed — with the exception of 3D games. Even Bugdom was a struggle (my youngsters used to play it on the thing). But then, a processor upgrade is not really going to help you there.
I still have that 14" machine and use it still more than most for this and that. The localtalk port, floppy bay, and so on makes them very flexible units. The keyboard is really superb — much better than a Pismo's (do not believe anyone, e.g. on LEM, no matter how illustrious, Canadian and bearded, who says otherwise).
I also have a fair number of spare parts, by the way, should you need something when the time comes, as I obtained several spares as they appeared for small sums over the years in order to refurbish and give away, and to keep mine ship-shape. I became pretty adept at it, and must have stripped down various WS machines completely twenty or thirty times. I have no spare large RAM chips, alas, though I do have a sizeable number of small (32MB, 64MB) ones.
Frankly, though, I would not fuss over a Sonnet upgrade for a minute. A 266MHz WS is already a slick, genuinely "old world" PowerBook for OS 8.1-9.22 work, and it will even run X.3 relatively well if you have the RAM for it (X.3 via xpostfacto). I would judge it to make much more sense to spend the money on a Pismo if greater speed in OS9 or if OSX on a classic 'book is desired. Unless you are doing something crazy like encoding mp3s on the WS, you will not really want for more megahertz. Most everything is perfectly snappy already.
I used a 14" WS, 266MHz, daily for several years in OS9 and it never really disappointed — with the exception of 3D games. Even Bugdom was a struggle (my youngsters used to play it on the thing). But then, a processor upgrade is not really going to help you there.
I still have that 14" machine and use it still more than most for this and that. The localtalk port, floppy bay, and so on makes them very flexible units. The keyboard is really superb — much better than a Pismo's (do not believe anyone, e.g. on LEM, no matter how illustrious, Canadian and bearded, who says otherwise).
I also have a fair number of spare parts, by the way, should you need something when the time comes, as I obtained several spares as they appeared for small sums over the years in order to refurbish and give away, and to keep mine ship-shape. I became pretty adept at it, and must have stripped down various WS machines completely twenty or thirty times. I have no spare large RAM chips, alas, though I do have a sizeable number of small (32MB, 64MB) ones.