twin pipe bog at low-mid throttle??

[maxwell]

stiffer rave springs? they only activate above 6500rpm. or so. weird

 

[Smurff1000]

stiffer rave springs? they only activate above 6500rpm. or so. weird

With all the New air coming in they helped,
stock one must of being opening sooner with all double the air.
at 4500 to 5000 when hit hard noticed.
Came with the pipes and helped with the bog and rpm rise.
(no missing feeling).