More 'rehab' than 'customization', this Part 1 article has some good pointers on upgrading / rehabbing a 1992 SR5 ... http://www.trucktrend.com/features/tech/163_0208_1992_toyota_sr_5_project/
... And here's the second (wrap-up) article, concentrating more on appearance upgrades: http://www.trucktrend.com/features/tech/163_0212_1992_toyota_sr_5_project/index.html