chances are the engine will already have VVT on the cams for more economy. the block itself is a bit more backward compared to most new engines as its a cast block rather than an alloy one. this is to save the strain from both chargers. VW dont really like blow off valves (or dump valves ) as they prefer to dump the charged air back into the inlet manifoldthink this is to cut the lag time. if you want the noise forge do a range of splitter valves, sends enough air back to the manifold and dumps the rest to air.
dont think youd need forged pistons until the powers getting silly, think 250ish bhp