I have heard arguments both ways

1] buy the best car you can and go from there

2] buy the cheapest you can find and start there.

I'm 70 now, and thinking to retire in a year or two. My retirement gift from my wife is a mid 60's-mid 70's restomod. Either finished before purchase by others, or a basket case that I have done myself, to my spec.

The backstory. In 1963 when I was just 12, Studebaker came out with the Avanti. i immediately fell in love with it, and from then until my last move about 10 years ago I had an AMT Avanti plastic model car. I've lusted after one for all this time. About 10 years ago, I almost bought one, but it just didn't happen. Now, once again, I have a chance.
The choice is: do I buy a well preserved one, (price range 20-30,000 U.S.)and modify it, o4 a car in need of work(I have 4 on my list right now: one for $1500, one for $3000 (both run and drive) another for 6800(doesn't drive)and another for $8800(no motor, good body).
In an ideal world, It will get a crate engine, new interior, new front chassis clip(Art Morrison makes one specific)and of course a slick paint job. Believe it or not, my wife is ok with me spending this much money on the car, provided I sell the Jag.
I'm inclined to go for one of the cheap ones, since I'm replacing so much of it anyway, but I remember seeing Boyd Coddington and Dave Kindig, and Danny Koker saying get the best you can.
Of course, an Avanti is fibreglass, so the rust issue won't be there, so maybe the starting condition doesn't matter.
Not particularity looking for consensus, just opinions, or experience.

We are also planning to restore my son's 89 Foxbody coupe(Hammerhead on the board has made an offer to do the paint/body), so I hope to have a busy retirement