Krell s300i to replace acurus/aragon combo?

I currently have an older Acurus RL11 preamp that is driving an Aragon 4004 mk2 (1996 model). The amps left channel intermittently cuts out. I was looking around for something a little newer and I see a new Krell S-300i integrated for $1750. I have Magnepan 1.6s and listen to an eclectic range of music. Would I be better served by finding a new amp and sticking with the old preamp or finding a decent integrated?
My budget is tight at $1800 which doesn't lend well to replacing both pre and amp.

If I get a better amp I fear I will then be handicapped by the pre..
Any suggestions?
Are you absolutely sure that its the amp? A channel can go out on a preamp also. To test it, just swap the IC's on the back of the amp. (l to r, r to l). If the right channel goes out after you swap the cables, its something else other than the amp.

Regardless, I don't think the i300 will be an improvement. If you want to try Krell, look for a good used KAV-250a. I've seen several of them come up here recently well within your price range. It would be a huge step up from the Aragon. That said, if your amp is working OK and has suficient power to drive your speakers, a new preamp should give a bigger improvement in sound quality.