This is a service provided by us. You send in your manifold and wastegate flange and we will modify it for use with external wastegate. We start with your stock SR20DET cast turbo manifold, sand blast it and clean up the castings on the runners. We then bore out a hole, where we will be welding our pipe section and wastegate flange of your choice.. These manifolds are the kicker for making some serious HP/TQ on a bottom mount/small framed turbo on an SR. We've seen 250/260 on a T25 SR/550's/38mm EWG/Rom/Z32 Maf/Rom tuned on 1 bar (14.5psi), and we've seen 290/300 on a S14 T28/550's/38mm EWG/Z32 maf/Rom tuned on 1 bar!