Stock as possible is always best as modded cars tend to be looked at as cars ran the piss out of.
And you will get more money the vast majority of the time.
Case in point, not apples to apples but an idea of what I have been through(many cars built and sold later)
2006 Vette convertible, $30k in mods, at least $40k if had the parts installed, offered at $39k, NADA was $37K at the time.
Posted it on the best Vette forums and immediately got posts about being over priced etc...the car had 19k miles, less than 2k on all the mods....
Put it on the lift, back to stock as close as I could make it, traded towards a new Duramax dually, got a very good trade, sold all the parts easily, $30k more in the bank, really.
That is an extreme example of course and not one I will ever do again as going to enjoy my FiST for a long time, I like it much better for real world use than the Vette
