[grumpy]

brian,
This question is posed every now and then. The field is strewn with over 40 "builders" of COBRAs and eliminating the advice based on personal favorites, quality versus quality, whether from an enginners viewpoint or an architects, and so on. To narrow the field by a big slice you need to decide on a true detailed "CSX3XXX" replica car verus a "hot rod skinned" COBRA 427 bodied kit car.
The first hurdle you must ask and solve will not be the money you spend totally but;

A. Originality
1. replica of original 100% accurate
2. FGRP skinned replca 90% chassis
B. COBRA shell on Hot Rod chassis
1. replica body on rectangular tube chassis with FORD driveline.
2. Kit body on rectangular tube chassis with assorted brand chassis and driveline parts.
C. Custom Cobra (do it the way I want)
1. Anything goes!

It's a matter of SAAC's interpertation, show judges, the prurists in the COBRA world, and viewing against the original design.
It's really not that hard to decide, who has a correct 4" tube steel chassis, who has the correct suspension, who has the correct body shape, who has the aluminum interior panels, the rest of the items to complete it will be supplied by you and your assembly or a "builder" to complete the process.
You can buy an original rolling chassis COBRA for less than most of the Hot Rod chassied versions, so it's not a matter of money to go to original specs.
If you go with a true "replica" COBRA of a known car there are great people on this forum that will keep you in line. If you pick a COBRA copy, then there a great many skilled others that will help you on the variety concepts and their completion.
Grumpy