The money and attention needs to go to chassis setup first. You'll need to greatly lower stance to cut the wind from underneath. It's even more important than drag racing sense low pressure under the vehicle has more time to generate. Which causes lift. Spoilers and wings to counter only adds drag that bleeds off energy produced by engine and drivetrain output. It's why Nascar has the splitter and stance so low to the track. A Bonneville build is typically significant higher speeds. Weight is an additional concern.
It's almost like designing an ultra light aeroplane. But in reverse. With no lifting wings of course.
Engine is actually easier. With many options today to make the power needed for 200+ MPH.
The challenge is not as popular because in the end you have nothing that is usable other than a top speed attempt. Most need external push to get going due to the extreme high gear set.