Online version:
http://www.mr2-tech.com/bgb.htm
To buy an actual copy:
http://www.poweredbytoyota.com/repairmanuals.html
might try partznet.com as well ...
"1991 Toyota MR2 Repair Manual - Volume 1"
(Engine and Specifications)
Part numbers:
First printing - Feb 28, 1990. 01-900228-00
First Revision - Jul 5, 1991. 02-910705-01
"1991 Toyota MR2 Repair Manual - Volume 2"
(Chassis, Body, Electrical, Specifications)
Part numbers:
First printing - Feb 28, 1990. 01-900228-00
First Revision - Jul 5, 1991. 02-910705-01
"1991 MR2 Electrical Wiring Diagram Manual"
Part numbers:
First printing - Jan 26, 1990. 01-900126-00