Your young and why not dream whilst you can before wife/kids/mortgage and life in general catches up with you
Dont expect a Covin to perform half as good as the cheapest C1 can, modern cars are a marvel of engineering, covins in my opinion are beautifull looking cars, and not anything to do with speed.
I built mine in 1990, and just enjoyed the attention it got parked up at shows or driving local.
A genuine 911 is tail happy (watch Dave Top gear) and thats packed with all the years of Porsche development and technology, so unless you value your life and your insurance, dont be tempted to see just how fast your Covin car can go, just because the motorway speed is 70 (8o mph in the future) doesnt mean you have to do that.
I drive a modern car and 60 is fine. No matter how fast you go, someone wants to pass you.