Hi.. I am researching a turbo kit for my car and have read about people using the L26/l36 Intake manifold compared to the blocked off M90 case. What are the benefits to this setup compared to the M90 casing?

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1996 Buick Riviera
3.4 ZZP mps, ZZP 1.9 rockers, Intense OR pushrods, CC 105s, Pacesetter headers, W-body store LIM , UD WP Pulley, DHP Powertuner, CAT delete
Suspension: Eibach STS springs , W-body store Gxp brake kit. Strut tower brace.