The Townshend Isolda DCTs are pretty neutral and transparent, so you get all the qualities of the recording coming through. Don't know about the DCT300s.
With the Isoldas, if the recording is full-bodied, warm, airy, light, or whatever, that's what you get. On the downside, if the recording is lousy, it stays lousy, warts and all.
Try to borrow a pair and listen to your system with them in place, if you can. I got mine used on eBay and saved the burning in time and a packet in cash. You could buy a pair on eBay just to try, because you can always resell without losing much if you decide against them. The internconnects usually go for £70-£100 per pair. Speaker cables vary a lot more, depending on length.
I do hope that I don't live to regret replying to your post. The cable naysayers are so ready to descend on anyone who thinks that cables do matter.