Anyone have any experience with the Tunami GPX-R ?

Yes.. purely aesthetics.. I got it at Take Five Audio in Canada.. While Christ VH sent some techflkex free with the plugs and cable i bought from VH Audio I wanted the softer Nylon Material I found at take Five. It was difficult to work onto the cable till i tried some powder on the cable and got it to slide without streching.. I haven't used heat scrink on the ends..not sure weather I'll eventually do it but I don't move this cord often so I will probably leave it as is.

I own two GPX-R (white plugs; for power distributor and integrated amp) and I am waiting for a third one for my digital source (instead of the GPX, red plugs).

GPX is a very dynamic cable with a strong mid-bass but it hides some microdetails in the higher frequencies, resulting a "dark", "warm" sound.
Recommended for systems weak in the bass and/or too bright/harsh on the top.

GPX-R shows even better dynamics, great bass strenght and definition, real neutrality with very good details, focus and soundstage, an almost universal cable, recommended for all systems.

12-08-10: Biggy79
GPX...hides some microdetails in the higher frequencies, resulting a "dark", "warm" sound.
Recommended for systems weak in the bass and/or too bright/harsh on the top.

Completely opposite in my system.

When it comes to wire, there are no absolutes.

The difference you mention between GPX and GPX-R is interesting. It is the same exact cable. The only difference is the connectors.