Maximum wet weight of 1000kg.
You would use an aftermarket computer.
Rear wheel drive
It must have NO LESS than 400kw atw
You want to build this as inexpensively as possible. (imaginary figure of 10-15k

The engine must not be a grenade.
Most of the work you can do yourself(except machining).
What engine would you use?
What would you do to said engine to get 400+kw? (you can't use nitrous)
Bear in mind that you would want to avoid spending loads of money on expensive branded performance parts.
What car/chassis would you use to keep within the weight limit?