I agree with Bjorn, it depends the condition of it now. My Firebird is very clean and original except for trans, rear, and possible engine. Therefor, when I get my house in order, I am going to upgrade the engine, trans, and rear axle.
I am going to keep it close to original but you are going to know when you open the hood it is not original by all the chrome and some upgrades.
I plan on being buried in mine or donating it to a museum as the crazy guy's car who built the FGF web site.