If you are +1" now, you will get to +2.5" or +3" total with the BP 51.

I call +1 the actual normal height for the 4R. I think it is lowered for the US vs the Prado platform. The CVs are reverse angled at the stock height and perfect at just under 1". So anything from 0 to 2" of lift is good. I think this is also why +3" is not a big problem for the CVs. Because I think it is really +2.

The one issue is wheel travel, very debated on this forum. See, most people don't believe that you get +1" from the Bilstein Pro and the 6112 but you surely do, just as Toyota said in ads. No need for aftermarket UCAs to get it. It is there, just underdone with the stock front. But I don't know how non-Bilstein fronts handle that. So to do it right for offroading at +3", you have to spend a lot of time and money, UCA and all. To do it right at +2", you need nothing but new coilovers. So lots of pain for half an inch of clearance!

Now, the 5100 series is very cheap. I guess it should handle pretty well on the road and will do any rock crawling and regular forest roads just fine. But once you start really using it, like driving faster over rough forest roads with embedded rock, it will not do well. It will get harsh and won't last very long, I bet. In the desert, that much less.

Also, be careful with rear shocks. Many are advertised with a big range which makes no sense. They should be advertised for 1.5" of difference, like 0-1.5 or 1.5-3 or 2-3 or 0-1. The Icon 2.0 advertised for 1-3 should really only be 2-3. And so on. It matters a great deal where the piston is at rest.

If the rig's offroad exploits are mild in length, roughness, OR speed (choose 2 but not all 3 with lower-end setups) then the 5100 may be all that is needed. Speed as low as 20 mph can be far too much for small shocks under the right conditions.