Naim CD5x versus CDX2

You would have a hard time making them sound bad.
Good solid shelf, any quality audio rack, is all that's required.
If you want better:
Naim Fraim....pricey
Quadraspire...nice looking reasonably priced. I use that rack with a Nuence platform under my CDX2, seems to help.
I would not recommend Points or anything that elevates the original feet off the surface. Naim designed these feet to be optimum. The CDX2 feet are hard, CD5X are softer.

I agree with musicat and perfectionist cd5x very good but cdx2 noticeably better. XPS takes it to new level, more open and detailed. CDX and xps can be found used.

Well, I've always isolated all my cdp's. I currently use Aurios Pro and Pro-Max bearings under all my gear, including amps. But I really never noticed the Naim cdp's being any worse than others w/o isolation. I'm a firm believer in isolation thru my own trial and error...

Again, check here:

http://forums.naim-audio.com/eve/forums?a=search&reqWords=CDX2+isolation

You can find every question about Naim that you can think up on the Naim forum.

Naim players in my experience are really good. If you read the Naim forum you will find the members are somewhat split as to which is better between the CDX5 (or CD5) and the CDX2. I owned both the CD5 and CDX2 at the same time with each on a shelf in my stand. I compared many, many times trying to choose the CDX2 which I slightly prefered the look. On some days I would just listen to one or the other. Ultimately the CDX2 was too aggressive or bright compared to the CD5. The CD5 has a laid back analog qualtiy about it in comparison. It gives up very little in detail and does not have the shouty quality the CDX2 has. Adding a separate power supply to the CDX2 alleviates the issues with the CDX2 but puts it in a whole new price category. I currently have the CD5x and it does not have the aggresive qualities of the CDX2. Some may argue they like the aggressiveness of the CDX2. It does exhibit great control but I would guess they have not directly compared with the CD5 or 5x.