# for car?

[570hp-lpe]

How do I know what # to use on my car for SOLO?

[Mickle]

You pick your own.  Make sure you are using the correct class lettering. And its always good to check through the previous events (particularly your class) to make sure you arent picking a number that someone else normally uses.

[Neil Schelly]

When you register, you won't be allowed to select a number that someone else is already registered with too.  But yeah, everything Mickle said is good practice.
-N