I felt my Pacemaker with the same kit and BGM exhaust was geared too low so I put a standard 150 box in and it pulls well in top with more speed but you do notice more sluggish acceleration but you can't have everything.
I went for 4,98 with 46-17 on my pacemaker box with a RT195 and MBGM CLubman. It gives me enough of both worlds regarding speed and acceleration in town.
Hi m8 a lad I know had a mugello 180 kit with Li 150 box he had 15x46 sprockets which I thought was just right with a a/f 42mm box exhaust, he was advised to try a 16 x46 but he sold it before it was fitted