with my 2005 PLUS 4 with the 80km/h and former 90 km/h speed limitation in France I found that 5th gear at 2200 rpm is too low and I generaly use the 4th (2500/2900 rpm). Sport cars must have short and close ratios. 3000 rpm is half of the maximum rev and doesn't stress the motor. If you always use low rev your motor will stay lazy with poor accelerations and cannot get its full nominal power.
It sounds to me like you have the 3.7:1 rear differential, which does tend to make for more of a tourer rather than a sports car feel.
TBM (and I) have 4.1:1 diffs, which keeps things lively, even with the .84 ratio 5th gear you're still doing 3000 rpm at 70mph. On minor roads like you I'm in 4th gear more often than 5th.
