For us DXers that don't have an RPM meter.

I've seen this meters mounted on the side that measure RPMs. DX rides don't have the RPM meters on the on-board dash, so my question is or are.....

1)Is it difficult to get one of those things installed?
2)Where would I buy one of those at?
3)How do I install it?

Guys! I know I am being a pest but this is the best damn forum I've been in.

Keep on racing!