Mystery Option Codes

[M@1975]

I've looked at most of the available resources fro decoding option codes and have deciphered most of them but still have some I can't track down, does anyone know what the following mean?

C18
XKX
XRL
XSR
XSA
X9C
X47
X58

i have a few more mystery numbers: 000051 00161 09991 21451 21631

Any help appreciated, I've tried Kindel and the lists on both Openpitlane and Rennlist but can't track these last ones down.

[sleep envy]

C18 is the country build code - t'internet says it's either UK or Japan which is odd as I thought the UK code was C16

[ScottMc91]

Don't know if these are correct but....

C18 Graphite gray leatherette linings in all areas (up to MY 1999)
XKX Lower part of instrument panel painted silver
XRL 18 inch sport design wheels
XSR Bucket seat, right, backrest in carbon
XSA Sports seat rear side of backrest painted body colour
X9C ??
X47 Carbon handbrake
X58 Carbon gear lever

9991 Exclusive Build programme


taken from here
http://www.autosport911.com/codes.html