separate amp or upgrade HT receiver?

I have a pretty inexpensive budget system right now... I have a HK AVR 235 (surround sound receiver) paired with KEF Q5 speakers.

Many reviews say that the NAD T7xx and ROTEL RSX HT receivers are far more musical, more dynamic than the typical HT receiver.

The HK AVR 235 has preamp outputs for all the channels.

If I wanted to improve the musicality of my audio system, should I just replace my HK with a NAD T743/T753, ROTEL RSX-1057 etc, or would I be better off keeping my HK receiver, and, say, get a separate stereo amplifier like a NAD C272?

If I am better off buying a separate power amp, are there any advantages at all to replacing the ht receiver?

Thanks so much.
If you wanted a good one box solution buy an NAD T753.
It has all the power and features you need with the Q5's.
Biggest bang for the buck in the line.

It would be a better long term plan, however, to get something like a Parasound 5125 multi channel power amp. It would improve the sound now (not as much as getting the T753) but afford you much better sound later on.

Surround sound is not that demanding so you could eventually get a good 2ch pre-amp with HT pass-through. Whenever you feel the need for "better" surround sound you can just get a latest-and-greatest Denon AVR.

Surround sound receivers, pre-pros, and DVD players are outdated by the time they hit the shelves.

Good luck!
The single biggest improvement in my HT system using a receiver was to add an outboard 5-channel amp (in my case, a Sherbourn 5 -1500). I used my receiver as a preamp processor and was very happy with the sound. I would suggest at least considering that route.