Hello Mr T,
How good to see you posting and enjoying your music still. I trust the family, house, garden, and work are going well.
Did you finish that 3 way speaker project? I would love to hear them as your previous 2 way pair did you credit.
You would definitely benefit from, and enjoy, a power amp upgrade. Foot tapper's words are absolutely on the money. My main point is one of encouragement. You may recall I went from one 250 to three (active yes, but a type of power amp upgrade) and despite the cost I never regretted it. You won't. And your 52 is good enough to beef up the power side.
Here's a suggestion, why not do it in stages and enjoy the journey? You could get a pair of serviced 135s, and the sale of your 250 will pay for one of them. Run those and perhaps get 300 later, and if you do, have it DR'd after. That way you spread the outlay and get real improvement each time. Its two boxes whichever way you go, so the same. Either two olive ones to complement the 52, or two black ones to complement the CD player.
Did you ever get a Hi-line over the stock inter-connect between CD and 52. A must if not, really.
Very best regards