With Respect
Not wanting to debate what can be a super technical discussion involving the various properties of resins and laminate/composite engineering..I will refer any interested parties to the following FFR site moderated by a professional auto car refinisher who has, over time, perfected the fine art of repairing and refinishing cobra bodies and who I believe has repaired/painted a variety of cobra bodies from a variety of manufacturers.
http://www.ffcobra.com/FAQ/body2.html
Note his comment : I grind the seams and cut the body open and fill the seams with 3M vinylester blister repair filler in one day.
There are very real advantages for the use of Vinylester, read the various posts on the subject in the forum "Ask street rod painter"
http://www.ffcobra.com/cgi-bin/ultim...1000&submit=Go
Lastly, Many have used the west systems epoxy resin in preferance to 3M Vinylester. ( also commented on that forum) This I do think is an overkill but, if one wants the best...why not.
I guess it is similiar to the finish we use on our cars. Mostly we use a colour coat and a clear top coat over predominently an epoxy primer surfacer. Why do we use this top of the range finish product when a lesser refinish product will do the job??...because we want the best!!!. We want it to look great, and look great for as long as possible.
Using that same argument...why not use the best top of the line repair systems/fillers under that top of the line refinish?
Cheers