Well I've added a turbo to an Integra GSR so I can tell you what I had to do. It could be different than the Rav4 but I haven't done any research. I'll also skip the part where I rebuilt the engine with lower compression and have the ability to boost 16lbs safely.
1) Verify your tranny will hold up or start looking into companies that can rebuild you a more bulletproof one.
2) Since there's no piggyback unit, assume you can only safely boost 6-8lbs. 6 for daily driving and you can crank 8 sometimes.
3) Since nobody makes an aftermarket ignition system, also assume you can't retard your timing. Which means you'll need to run higher octane gas
4) Check the size of your injectors and make sure it can pump enough gas.
5) You'll need to increase the pressure in your gas line so get a fuel rail and a fuel pressure regulator.
6) I'd run an intercooler if I were you
7) You'll need something to monitor your a/f ratio and adjust it.
8. Gauges to monitor everything. FPR, turbo, oil temp and some sort of pod to mount them (and you can't use pillar mounts due to airbags)
9) The all important turbo timer
10) Boost controller
11) money to dyno tune
13) heat shield
15) External BOV
That's what I can think of off the top of my head right now.
Cars, snowboarding, house modding.