Not just manual transmission. ..As I've pointed out the GFB seems slightly better all round on a DSG vehicle as well .
Rupert, if you can do logs on boost, which you can get details from APRS site on what to log, you'll see for real what the story is. Smooth is fast. Maybe the CTS has a placebo affect. Maybe it is faster. All in all I think a WORKING valve should give you equal results
Hey rupertpupkin I'm pretty sure you had a fake GFB DV+. They were going around a lot back then and here is a video explaining the difference. If the link doesn't show just google "how to spot a fake DV+" and it will be a video showing them side by side.