you'll generally be far more successful if you stop and make careful choices in the basic car,
you select and think through your options, factors like the brand can be important, example an AMX may be cool,
you should keep in mind every choice made is a compromise in some areas, planning is critical, but reality can bite you in financial the ass.
incremental gains through minor mods while surely possible and yes proven, to work,but adding those mods,
are at some point ,mods to the engine,or transmission, that are becoming rapidly more, expensive and thus restrictive to completion of a durable & functional engine than the benefits are to the overall build, those mods may produce minor and documented gains, but the minor gains produced are far out weighted by the cost of the mods, especially in a daily drivers engine, things that make sense in a formula 1 or NASCAR engine build, are cost prohibitive to do on a street car, simply shedding weight on the car or improving the aerodynamics, may be far cheaper and result in greater performance.
I've built a few dozen 489-496 BBC engines in the past for guys with novas, camaros chevelles etc, that had visions of having a 10 second or faster car on the street, and the results of having a significantly more powerful engines always resulted in the need for mods like suspension mods,
like traction bars, air shocks, bigger tires, bigger brakes, better engine cooling systems, new stronger differentials, etc. that they may have never considered, that were required to make the car handle correctly, this is never a cheap hobby, but at some point there's a limit to what your wallet will tolerate and how long you want to deal with a car who's engine is (STILL UNDER CONSTRUCTION SO I CAN'T DRIVE IT YET)
but parts availability on a limited production run car from a less popular brand limits your component choices.
drive train, etc. rather than how most people have gotten into muscle cars,
which was buying a muscle-car and just dumping performance parts into the existing car.
choices like a CORVETTE or camaro,, Plymouth barracuda, mustang, or GTO allow you to have a much more extensive list of parts to select from.
the choices you make in the cars wheel base,
power to weight ratio, and the suspension and drive train.
ALL effect the final results.
I know several people that built AC, cobra replicas and T-bucket cars,
mostly because they allow easy access to the drive train components in a combo,
that has potentially a very good power to low weight ratio,
thus performance is potentially improved