on the sequential turbo setup the most commonlly tuned car that had them is the 93-95 usdm rx-7. the rx-7 acctaully has to same sized turbos but at but a butterfly valve closes off the piping to one of them until the car hit somin like 4000rpm the both are opened up this allows for a quik spool to get boost in the lower rpms but also more boost up high