Krell KSA 250 - Advice

Heat hurts electronics. Krells of that age sound the best they say, but can be used for cooking your Sunday Joint. Try to get the seller to defray inspection and servicing costs which should be only by a Krell authorized service center. Which is an expensive endeavopr here and in th UKL I imagine as you say a p[remium over that.
Isn't VAT etc paid?
The original price won't have a huge impact. The used price with most reasonably current equiment will be around %50 of the original price. With older stuff the used price may not be lower but instead what the market demand now allows. If your lucky no one ever heard of Krell and everyone wants a Beard amp.
Musically it will be compatible and probably very nice. If you like a wallop in the bass octaves very few things beat a Krell in pure class A, prior to the Plateau bias curcuitry. However Like all things audio no one can predict whether you will like it.

If the electrolytic capacitors are the originals you should consider replacing all of them - it is not too expensive, and you have an amplifier that should last for more 20 years if you use high temperature types.
Be sure that your preamp can drive the KSA250 and remember that it must be switched on at less one hour before listening - sound from a cold unit is quite sterile.
However there are some good news - the best sound I ever heard from a pair of Sonus Faber Extrema was when they were driven by a KSA250 that has been playing for several hours, although the ARC Classic 150s were also very good.

I have a friend who is a technician and he showed me a large Krell [forget number] that someone had given him because the expense of putting new caps in was more than he had thought it was worth. I am a former Krell dealer from their early days and am not very taken with them. I would take a look at the Audio Synthesis amp, Desire Decade I think, currently on ebay for 850 pounds, I have some of their equipment and it is very good, I would get the amp but for the freight and current conversion costs. I would also look at the Musical Fidelity NuVista M3 or TriVista or GamuT if any is available in your price range. But look at that Audio Synthesis, not a big name but a serious company.

I owned a Krell KSA-250 for quite some time.
Eventually it needed service, sparks and smoke...yikes!

Anyway, I sent it to Krell and they charged about $400 (including shipping) to bring it back to spec.

So, probably if you find a used unit that has not recently seen service from Krell, expect to send it to Krell for updating anyway.

I did eventually sell the KSA 250 for about $2500 a couple of years back. So, current prices should be a little below that price range (if its been updated).

Great unit, puts out a lot of heat.

I purchased my Krell KSA-250 used several years ago. Next to my Yamaha NS-1000M speakers, probably the best HiFi equipment I have ever had the pleasure to own. I will never sell this amp! Two years ago I sent the amp back to Krell for a refurbish, cost me $600 I think. The amp now looks and sounds perfect to me. With respect to voltage conversion, unlike newer Krell products, the KSA is very easy to change voltage on (there are 3 jumpers inside that need to be set). I heard Absolute Sound in the UK charge £300 to do this, obscene the job takes less than 10 minutes! My advise to you, pay extra and find a KSA-250 that has been refurbished within the last 5 years and enjoy for many years to come!