I noticed the same thing after adding more fibreglass to my Raask pipes, to quieten them down a bit. Once I did this, the bike seemed to accelerate faster, but had this surging at higher speeds. Thought at first it was just the wind buffeting me, but there is definately some surging going on. Thought I´d just have to get used to it, but maybe should try the TBS needles as well ?
/Tiv
