[decooney]

-Engine can be a big variable. (i.e. Shelby Block build vs. 390 FE std block)
-Body/Paint is a big variable.
-Differential/options is a variable.
-Wheels/Tires/hubs can be a notable variable.
-Standard or custom-upgrade suspension is a variable.
-Bits and small custom parts are a varable.
-Other Outside LABOR can be a huge variable if you farm out work.
-The rest, for the most part is pretty much standard.

I've seen ERAs range in spread as much as 5k-25k depending on build/option/upgrade differences depending on many of the factors above. DC