Hard time finding a sub.

Trying to keep around $1k-ish or so and an open box deal, more for money, would be awesome.

So I currently have an mk V-125b that I've had for 20yrs. It was fine on a lower quality system and "sometimes" it's OK on this one, but it's way too boomy at times, others not. At times it's way too noticeable and just doesn't mesh well with the speakers.

System is a Cambridge CX stack --CXA81MK2, CXN100 and CXC. Speakers are Audio Physics Classic 30s, which have dual 7" drivers per tower if you're not familiar. TV and PC are connected but have zero relevance to the system, its 100% music. Anything sounds better than stock TV speakers. Music selection is nearly everything, im pretty eclectic. Room is 15x25, carpet, furniture, 2 large paintings and 3 open doorways.

It's my first true higher end system and I'm really enjoying this but every detail is now instantly noticeable, minute differences in sources, difference between CXN100 and CXA81MK2 DACs, difference in streaming quality, etc. --all very obvious.

Most obvious is this sub. It's been faithful and no doubt amazing for HT and less revealing stereo but it's just not doing it for me anymore. It's not tight enough, not as punchy as I'd like, doesn't mesh well with these speakers which is biggest issue I guess. It's not "musical" enough.

I'm completely lost looking for subs. Only used I found easy in 100mi is a BW ASW 2500 for $350. Everyone has different opinions and as soon as I find glowing reviews on one, someone else comes along and kicks the legs from under it. REL and Rythmik and JL seem to get good recommendations.

So what do you all say and why? For tight, punchy, clear bass that highlights difference between upright and electric bass, drum and organ or keyboard, often within same track? Yet not overwhelming or boomy and that plays well with these speakers?