[ack fia]

Here is a list of the things I would have added to my FIA if I were to do it again:
Optional outboard brakes on the rear.
Fuel cell tank.
Fuel shut off at the tank (operate from the drivers position).
Kirkey "vintage" race seat (driver).
Relocate the shifter to a more forward position.

If you are going with a Jones Motarola mechanical tach, I'd opt for the 4" unit, it will fit.