| My ST2 mostly standard apart from cans, chip and 14 tooth sprocket does about the same (about 140-150 miles between fill ups).
But what's a fill up? Being a wuss who doesn't like pushing bikes to petrol stations I always fill mine as soon as I'm able to once the low fuel light comes on. I usually put about 15 - 16 litres in once the light shows (I know, I know, I've still got 4 to 5 litres left when I fill up which is loads for a 996 pilot) so 140 divided by 15 or 16 is about 8 to 9 ish miles per litre.
It's in the same ball park so pipes, chips and smaller sprockets don't seem to make much difference | 
Jools
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