Is it better to build a project car vs. buy on these days?

I want something fast, fun, with a manual transmission. 700hp minimum.

Nearly every car I look at is expensive though. Supra, Nissan Z, Mopar. Not to mention I'd be dealing with a car note.

I figure it's better to buy an old car with a good platform to build on. The only downside to old cars is that they're also getting expensive. A 2003 Terminator or WS6 is easily $40k. Also I hate old tech and ugly old interiors, so upgrading would be a must.

700hp is some stupid shit what u gonna run slicks to grip on sum 60 rolls on the fuckin freeway? yall niggas delusional bout errything round this mufuka, same as dem youngstas flexing they red key and sliding thru da intersection str8 2 tha grave

bet u done seen some ho in a supra on tha tiktok thinkin u finna get ya dick wet n run up yo amex just 2 pump nos in a fuckin old ass firebird wen nobody really give a fuck cept some tweaked out geeks with hand tats lmao. ud kno this if u ever left ya crib

get ya nuts checked

I have a modified Z, already in the process of selling it as I got a Aston Martin V8 Vantage to replace it. Had it supercharged and everything. It was a lot of fun but they are a pain in the ass when it comes to DMV and maintenance. Had a WS6 as well, kept that stock but it's a total muscle car, not much in the way of handling.

depends on the model, time
would day build if its cheaper
through a trusted mechanic/