Radio Wire Gauge?
 

Anyone know what gauge the speaker wires coming from the cd deck are?

The stock ones are thin... Maybe 18 or 20?? If you're trying to locate them amidst the harness into the door? They are twisted together.

Hmm I know where they are but my speakers require 18+

Anyone have any experience re-wiring the speakers? Should I buy high-performance wire? What about the age of the wire? Would that come into consideration?

There is no reason why the speakers as such "require" a certain gauge of wire. The cross section of wire is basically dependant on the current to be conducted and therefore the peak power/watts/volume involved.

Wire sold as high performance, is a con. The cross section and current carrying capacity is the only factor to be considered. It is extremely unlikely that the existing wires could have corroded or become frayed to the extent that overall resistance could be increased to any marked affect.

Unless you are subject to placebo, I would warrant that the existing wires will be completely adequate.

The gauge for the speaker wire is really driven by the vibration/thermal/abrasion that it's likely to see being installed in the car. I think a good 18 ga with a thick, flexible insulation will be just fine.
-Bill

Thanks for the responses :)