You don't need both. With a BANKS big head there is no reason for the PPE valve to be used. You may need to adjust the big head as that could be causing your low boost. Stock boost should be roughly 18-20 at stock fueling after the intercooler. With a bighead it should be capable of hitting 30-32 if you have enough fuel to do so. Anymore than 32 is a waste and pushing your stock IHI outside of it's comfort zone. And a good EFILIVE tune can really wake up the stock turbo. I have no complaints with mine being laggy per say. it doesn't spool as instant as an LBZ, but I have yet to hear somebody say it's a slouch off the line. Stock tuning was a different story.