hi i had a sachs dual mass fitted and atempt fitting of a manifold to my s3 amk 1.8 its been remapped by jabba stage 1 i recently fitted all parts to get it to stage 3 (turbo dynamics stage4 hybrid)etc.. anyway it was boosting around 18-20psi when it went in but when it came out its boosting any were between 5-15psi and its also bosting to 10psi then dropping off to 5. he attempted fitting the xs manifold but when he looked at the turbo one of the bolts was in bad condtion so it put him off.... any ideas on what it could be as the car was fine when it went in cheers