I thought the base power was 367 and there was an optional kit from AR Performance which combined with the sidelines raised it to the 390. Hi flow cats were part of it as well I think ?
The side exits may well be an Aero Racing product, but they won't include performance catalysts. The catalyst are an integral part of the exhaust manifolds.
As to the claims of performance gains, I'd call bulls**t
BMW tuners, on the same engine are only seeing slightly larger (dyno tested and proven) gains with full manifold and exhaust system changes.
Simon @ SiFab.co.uk
