I can weld over. T4 Holes are still within boundaries of t3

 

I think your a little confused on how it works. T3 T4 is just the style flange, they do make adapters to fit t3 on t4 manifold and vice versa but it's not worth the hassle and restriction. If it's a t3 flange style turbo you need a t3 manifold. T4 is for bigger applications but like posted before not as many options as t3. You can also just swap the hotside of the turbo to a t3 open scroll to match with your manifold. If your doing t3 manifold go with the gt30

 

In that case disregard my last post lol