Okay 2 questions
Question 1) Did I need to fit a longer rear belt - no. The stock one was plenty long enough. Its gone from being about halfway along the adjustment slot to just under halfway.
Question 2) Changing at lower speeds into 6th. Yup, I agree this is odd and not what I was expecting at all however what can I say - its how it is. WHat I have noticed though is although being in 6th now has much more range (previously, after 15k miles, 6th was something for 70+mph, before 15k it was 85mph and then into 6th, now its anytime from 60mph onwards.
What I will say is that while up to 90mph 6th gear has much more range, the gear up is more than the performance improvement from my stage 1 so not much left after 90-95. Where previously I could get up to 110 (obviously on a race track ....) reasonably easily.
Enter my topic on tuning up an EFI