will a receiver upgrade make a enough difference

My experience is that _any_ speaker, except perhaps one that's broken already, will let you hear an improvement in upstream equipment.

To try this out, maybe you could take your speakers in to a store which sells really good stuff--like maybe an Audio Refinement multichannel preamp--and see if they will let you hear the difference when you go _way_ up the scale.

Then decide if a receiver upgrade will make a big enough difference. You may discover you prefer to wait until you can afford to take a giant step.

If your older Mitshubishi doesn't have DD or DTS, you'll notice a big difference when watching movies with those formats. If you buy a new receiver with prologic II,you should get more out of your music and television.

I think that most of the Japanese recievers sold today sound alike (and not good at all) regardless of cost. Listening to new front end components (dvd players etc.) is a lost cause through most of the mid-fi recievers sold today; most of them just do not have the resolution to hear a distinct difference and it can be difficult to turn off all of the effects. If you were to upgrade your reviever I would definitely look into the B&K products. These components sound more like hi-end components than mid-fi and are priced within many budgets. I like them much better than the current Rotel components that I have heard. Changing the speakers will make the most positive difference in sound at this point. If you are not set on a new reciever, I would look into some better speakers first, then the reciever, and finally the dvd player.