[purpleRac3r]

In my research into exhaust for my non-NPP Stingray, I've come across only one that is a direct replacement for the NPP. It's the B & B Performance Fusion syste. It uses the stock valves on new mufflers and pipes, so the operation and ability to change settings stays stock. I've neither seen the system on an actual car, nor heard it in person, so cannot vouch for it, tho B & B systems are known for a pretty aggressive sound. There may be others out there, but I didn't see any.

As for advantages, about the only ones I can determine are louder than stock sound in both modes and slightly better power than the stock system. This would be true of both NPP & non-NPP cars. One big disadvantage would be dollars spent. You'll pay around $1200 for the NPP only to take half of it right back off, then pay anywhere from $1500 to over $3000 (depending on brand and options you ultimately go with) for the aftermarket set-up. Seems to me like you'd be paying twice for exhaust before you're done.

A non-NPP car saves you that $1200 right off the top, which you could then put directly toward the aftermarket kit. The power will be equal to that offered by the kits for NPP. The better companies tune their kits to minimize intrusive sound while cruising, yet really crank it up when you mash the gas pedal. To me, the NPP is best for those who plan to keep things stock, the base exhaust makes better sense if you plan to upgrade for looks, performance and sound. That's the route I followed, and intend to go with Corsa as soon as I collect enough $$.

Just an FYI, every kit I've looked maintains the V4 valves located before the mufflers. Some use just the valves in new pipes & flanges, others use the stock over-axle pipe sections. This helps for those rare occasions in V4 mode and prevent a need for programming changes.