Considering the options with a 300zx

[Bearr]

After a lot of reading and research I've come to three possible options for the base of my build: Buy an expensive but great condition low mileage all original 300zx TT and start modding right on all the stock stuff.

Buy a cheaper 300zx TT with a good body and interior but with just some kind of engine or tranny problem and have z1 replace the engine with a stage 1 long block for me to base my mods. (i'll be going for somewhere between 400-500rwhp I'm still working out what i can afford and want.)

Buy a real cheap NA 300zx and pay z1 to convert it.

There is benefits to all of these options obviously, the main point of me asking this is because I need people's actual experience not just all the numbers. Whats actually the all around best route from experience really doing it?

These are some of the numbers i've put together, I didn't spend a crazy amount of time looking for deals mind you.

New original low mileage car cost: $17,000 28,000 miles, all stock

Cheaper TT for an engine replacement: $4000-$7000, z1 long block stage 1: $4250+$3000 labor and parts(assuming the trade in or sale of stock parts)?also assuming you have to have a good transmission on the cheaper TT. I'm not sure on what the actual parts and labor come out to thats where i need help. I will do all new parts though, i want solid reliability and to just do it right. that comes out to arounddd the neighborhood of $13,000 depending on the deal you find?

Real cheap NA to convert, Car: $2000 Conversion package installed estimating $11,000? Plus the rebuilt engine and turbos for $4500 installed and 97+5speed transmission for $1850 installed. (thats optional depending what condition your stock is at, theres additional cheap parts to include on this to make everything new if you want) all together I'm guessing around 19,000


There is a lot to consider with all those options though, I don't really want to go into all the details (hicas deletion cost, NA higher gear diff, reliability factors etc) I'm assuming you know this and can tell me what you believe the best option is from experience. Also itd be great to know if i'm way off in my guessing of basic pricing, not going into too many specifics like transportation cost and stuff.
Thanks for the help