Some suggest a Marshall JCM 900 SL-X and a 800 KK.
Well, I had an '86 and '84 2203 and 2204 (JCM 800) and I also had the SL-X and KK.
The KK didn't sound like my original 800. Without the beast section engaged it sounded good for something like Status Quo (as a matter of fact, I saw them using these) but to me the KK lacked some balls and headroom. I always thought that it sounded more like a 50 watt amp. And engaging the Beast section didn't help that.
I don't say it is a bad amp but it didn't sound like my 800 (2203).
The SL-X , same story, doesn't sound like an 800 (on steroids like they were advertised).
My Friedman BE 100 Deluxe does a better job at sounding like an 800 (mind you , Gain structure at the minimum position; adjust voicing and gain to taste..)