Troy : You can get a 1'x2' piece of magnetic material from McMaster Carr (sp?) for only about $5.....or probably locally for under $10 (I know it runs right at $10 at the local crafts store, and that includes paying the "CA markup"
Then goto a sign (vinyl) shop and have them print out the numbers you need in 8" high numbers....6" could work, but will be a bit small.
It's also important to use CONTRASTING numbers. Having worked timing-and-scoring at more than my share of AutoX events, you eventually are about ready to throttle someone who can't make readable numbers....hell, just add a few cones (seconds) to their score and blame it on not being able to read their car numbers, and they usually understand quick [img]smile.gif[/img]
Here are the colors I'd recommend on an SS
BBB : White, Silver, BRIGHT blue (which is what I have for this year...one of the few colors that works on either car I own!), BRIGHT red, yellow
DCM : White, Silver, yellow
DGGM : White, Silver, yellow
Hope this helps!