I have owned my Kustom 200 since new in 1971. I thought I was the baddest in Atlanta, until I met a guy with an Acoustic 361..made my little Kustom seem anemic.
Eventually every guitarist I knew bought a Marshall Stack. I was mute against that. So, I bought a 370 head and powered it with a used Sunn 1-18 vh[ folded horn] which I LOVE.
Oddly, by the time I had a "decent" rig, I was no longer playing rock [ losing $$]. I was in a country band [ making $$$], playing Top 40 [ 1980s then] country and oldies; going up against a Fender Super or 2. In that arena, Kustom sat in well; equal in volume. Half the time I used my Kustom, especially when gigs needed lower volume; smaller clubs, where the 370 Sunn was overbearing and requests were more often for us to turn down. Our younger audience was my age now..nearly 60..LOL..
Back to 1971: I was nearly totally ignorant, as I grew up on poor side of the tracks, where Silvertone was a real choice, but Fender Bassman and Kustom was always the goal. While I was keenly aware of Ampeg sb 12 and 15, I never heard of SVT untill years later..LOL.. I tried Bassmans; low volume and little tone. Tube maintence was not what I envisioned for a fun hobby. SB 12 and 15 flip tops have beautiful tone, and even less volume than my Kustom, so they were never a consideration. Also, T-N-R Looks so much more modern/ cool than that retro 1940's look of flip tops..my opinion..LOL..
Also, I was totally unaware of speaker choices with Kustom: CTS, or ALTEC and JBL upgrades. As my luck would have it, my Kustom came with CTS. My only experience with a Kustom cab loaded with JBLs..[don't know which JBL].. was a 3x15 Kustom cab with JBLs at an audition; I was asked not to bring a cab; only my head. Now that cab coupled with my AC 370 sounded awesome.
Had my Kustom been loaded originally with JBLs, would I have been able to keep up with Marshalls?
People say Kustoms are loud, but mine sounds like Jack Bruce and Felix Pappalardi any volume past 10 o'clock or better; louder, yet far more distorted. Kustoms were "front loaded" for volume; little volume increase and major distortion increase beyond "noon".
Also, in order to realize the 100 watts RMS of the K200 head, I would have to use (2) 2x15 cabs. One Kustom cab is heavy. 2 cabs is a lot to lug just for jams. Of course, I was much younger in those days.
I have asked in the TB Kustom Club and a choice for weight reduction would be Emminence but that leads to tone vs weight vs BFM and the religion of x-max..lol..
K200B is a highly reliable amp. Mine has never failed to power-up; only issue with mine is with the "bright" switch, on the Bright side, which can be repaired. Of course I can use Normal side; just not as much treble tone.
As I have no gigs, I will neither be looking at repairs or speaker relacement in the near future.