It's not too bad. the controller is under the driver's seat and you just follow the harness forward from there.
The TVSS applies to 91-94 and had three versions, 91-2, 93 and 94. I know the 94 version fits a 93 as that is what I put in mine. 95-up have a VIP system that is different.
Vic,
The factory secutity system (in 94 it was a TVSS or Toyota Vehicle Security System) was an option, not a standard feature.
Unfortunately the installation kit has been discontinued for several years. You will need to pursue an aftermarket system of some sort.
D-