It mostly depends on your budget. Under $2k gets you a pretty solid self tuning throttle body fuel injection and timing control, but if you want to go multi port, it’s going to cost more.
The self tuning throttle body kits are becoming popular options even for the stock land cruiser motor. I have a Holley sniper on mine and love it. But there are several brands and models to choose from. Get on you tube and check out some reviews and some of the initial startups