Valve Seals.........Question

[Fastbird]

Ok, so I'm down to having to go ahead and do the valve seals on my car in order to get this cam swap finished up. Found some info on my old first gen trick flow heads:

11/32 valve stem diameter
.500 valve guide outer diameter

So I've got my dimensions right there for what I need.

Now, I have the direct trick flow part number they list as coming with the assembled heads:

Trick Flow Fluoroelastometer Valve Seals

But I find these also as other options:

Comp Cams Viton

and

Comp Cams PTFE

and

AllStar PTFE (looks to be same as Comp PTFE but cheaper

Now.......the question comes in...........which of these would be better for a street/strip car, seal better, be longer lived, etc? I'm a noob to valve seals. I know most folks seem to prefer the Comp Viton seals with the encapsulated metal body and spring retainer around the stem seal, but the PTFE's have a coiled spring and seem like they'd seal tighter, but would the difference in material come into play? I'm jsut not sure.........so guide me oh great ones.

[Fastbird]

Closer inspection of my car shows what looks like the Comp Viton seals on there right now. They're the same light blue with spring collar. I'm hesitant on those now because they're the ones leaking, I did fully verify this by looking down the runners and seeing oil pooled (not a lot, but enough) on the valves and you could see run trails coming from the guide.

But......would viton dry out if it was sitting undisturbed for nearly 3 years on an engine stand? Could I have simply let it sit too long before running it initially and they dried out and are leaking due to that?