With 4runners your so limited the 1.9 looked great due to the price for a swap and all the great comments about it. I asked myself the same question until I saw videos of people upgrading the 1.9 to a stage 1 or higher, and just assumed it was the way to go. I felt the 4bt is to big plus a money dump, and the 1kzs have really bad head issues. Those where the only successful diesel I've seen