I wouldn't mind discussing this point a bit more.
I'd like to upgrade my SL-1200, and have been attracted to the Jelco, but can't really afford it now. Is a tonearm re-wiring (and KAB damping) really the same level of improvement, or even close to it?
I own a KAB Technics SL-1200MK5 (Technics tonearm) with:
-Cardas tonearm rewire
-KAB tonearm dampener
I also own a Technics SP-15 with a JELCO tonearm.
I bought my Jelco tonearm before it was 'discovered' by the audiophile crowd and became the 'flavor of the month.' So I had no preconceived notions about it. Just that it was a reasonable price, looked to be of good build quality, and long enough that I could spin 16" transcription discs on my SP-15. In the time I've had it, I've played hundreds of records with it.
Based on my experience, there's not enough difference in performance of the two tonearms to be of any significance. I would advise you to save some money and buy the KAB upgrades for your existing Technics tonearm. The KAB upgrades make this tonearm a first class performer. Disregard any nonsense about the Technics tonearm being "a weak link." That it can be improved by those two modifications takes nothing away from the fact that its design and construction is of the highest quality.
As far as I can tell, the motivation for replacing the Technics tonearm with a Jelco/Rega/SME, etc... is:
1) An obsession to tweak & experiment.
2) A dogged determination to get rid of the "DJ" appearance of the turntable, in seeking approval of fellow audiophiles.
Either reason is fine if a guy wants to spend the money and time to do so.
If I were to replace the tonearm on my SL-1200, it would more likely be a
noticeable improvement, such as installing a high-end air bearing linear-tracking tonearm. But I don't think that'll happen simply because of cost consideration and overall excellent performance of the existing (modified) tonearm.
Have fun whichever direction you take!