Hang on a sec there, PPT, don’t be so hasty simply because of a few comments on here…
A 500 is indeed a tremendous amp, but I wouldn’t consider one unless I was already using a 552. If the 252 is a stop-gap (in relative terms) and your intention is to go for a 552 in the foreseeable future, then fine, assuming you also have the budget to get it serviced and DR’d imminently, it’s a cheaper route to full-fat 500DR ownership.
However, a baggy 500 in a 252-fronted system will not outperform a 300DR and if you’re planning on staying with a 252, then combining it with a 300DR makes real sense. It’s a great combination that’s heaps better than what you currently have.
As an alternative, and given how much you’re indicating you’re prepared to pay, I’d be keeping my powder dry until a nice used 552 came on the market and combine that with a used 250DR. IMHO that would be a much better system for the same outlay.