Screwie Lewie will return, revealed to be a double leg amputee. When he's not driving the Twister, he uses an all terrain wheel-chair called the Spack Chariot: This may be available to drive in-game..
'Screwie Louie' is a phrase describes something that is not working correctly, ie. "the printer's all Screwie Louie again."
In the PlayStation port, Screwie Lewie is called Screwie Louis. In this game he drives the same Twister, but during races there's no drill on the front. It has one on the Info screen and in the Car Shop, very odd.
The Twister is a heavily modified reworking of the Electric Blue, itself a modded Lister Storm. The Twister also seems, at least in part, to be based on the Lancia Stratos - most evident around the indicator lights and grille. The rear of the car, however, is definitely something else.
The Twister does not have a steering wheel - instead, Screwie uses a joystick.
The 'Screwie 2' could be a pun on the famous ocean liner, the Q.E.2.
Screwie Lewie will return in Carmageddon: Reincarnation, but his legs won't... his newest design has no legs. Not that we know if he had legs in the earlier games.
This could work as a good explanation (aside from insanity) as to why he drives using a one-handed joystick (which would allow him to control a throttle with his other hand).
Speaking of the Spack Chariot, 'Spack' is short for 'Spacker', which is not a nice word - it's a harsher version of 'retard' (which is hardly a politically correct term itself).