Seems that you like to build cars, enjoy them, then sell. If this is the case, I'd research resale stats & the features attributed to fast sales. In this case I'd suggest you buy used & save some money. & have a chance at recouping what you've invested.
A few of us around here bought/built our cars as that one dream car they might only once be able to afford & keep for enjoyment, for an extended time. In this case, I'd suggest you build it exactly how you want it.
There are a number of FIA mfgs out there these days. This should make your life more difficult
. Have a look at Factory 5, Unique & ERA. Kirkham, if you can stretch your budget that far & superformance for a roller that just needs a motor/trans.
PY close attention to what you get for the money & if accuracy or budget is more your game.