ive not had my rs long, so im a bit unsure about this....

what exactly is this fuel computer i keep reading about? ive read its only on 90 spec cars, so mine being an E reg, im assuming i wont have one.

does it fit somewhere on the speedo/rev counter dials? or is it a seperate unit? is it digital? what does it look like? and what does it do?

cheers for the help.