considering that the diffrence between a stock sami case and a stock kick case is less than the diffrence between a 35" tire and a 31" tire I feel its very relevent 
You didn't do well at maths at school did you? The difference between a 31 and a 35 is only 13% and the difference between a Kick and a Sammi case is about 41% and I reckon that 41% is bigger than 13%, not less than as you seem to think plus you have changed the diff ratios to help with bigger rubber and he would be changing them by an even larger amount in the wrong direction. As I said before, what you stated is not really relevant 
Just sayin that there is a lower gear than a 5.29, im sure you could run a 5.71 in a any zuk or track and it would be just fine.
I have talked to people who are running them in there toy axled Vitaras with no problems.
It was mostly the Toyota guys running doubler's with 40s that told me they were popping them.
Amilla