K-tec sell a silenced decat in the 2.5" bore.
Very effective at muting the sound without killing it completely (still provides top end 'raspyness') & still provides the performance benefits of a decat![]()
I swear this de-cat is no quieter than a normal de-cat, seems like a gimmic to me, here is my old system with the K-tec silenced de-cat fitted, not exactly quiet, was so loud at 70mph on A roads as well.