Dundon Motorsports is happy to provide the Cobb Accessport for the 981 GT4/Spyder.  We're Cobb Pro Tuners and have developed a great tune for the Dundon GT4/Spyder Race Headers.

Gains Over Stock including GT4/Spyder Race Headers and Dundon Pro Tune:

3600 RPM: +50 wtq +32whp
5000 RPM: +55 wtq, +52whp
5800 RPM: +24 wtq, +26whp
6500 RPM: +30 wtq, +36whp
7500 RPM: +30 wtq, +43whp

377.1whp on our dyno works out to 438.8 BHP