I think the stairs would work nicely for something modern or a race car. The transplanted hood side vents work but only in a functional way. If that car was a dry lakes racer, they'd be perfect. If that car was meant to be aesthetically pleasing, then they wouldn't because they are in a straight line while the hood is curved. Having said that, you did a great job doing the bodywork.
He means you have to buy a pre-built/painted collectible. https://www.google.com/search?q=die+cast+bugatti+veyron&hl=en&biw=1280&bih=835&site=imghp&tbm=shop&source=lnms&sa=X&ved=0ahUKEwidgsCOhvvMAhWBQiYKHThcAA0Q_AUIBygB&dpr=1#hl=en&tbm=shop&q=diecast+bugatti+veyron
After some quick math this Stude Carrera racer would likely be the fastest. With an L88 engine, Corvette drivetrain, and that slick (and low weight, only 2860 lbs) Leowy body, this one would be hard to beat on any road course.
This one is back on the bench. I hope to get back at it this week. I'm going on three weeks straight at work without a day off. I'll be going in a different direction though. I have the leftovers from these two kits after finishing my RPU. I'm going to use the modified cab from earlier with the 32 chassis. Front and back suspensions will be modified to get a very low stance. I may Z the chassis in the rear, but not the front. I'm going to add a suicide front end. I'll be using the grill, wheels and tires from the roadster and a parts pack Caddy engine. More soon. I hope.