Has anyone tried this? I have a 2007 5-speed 1.6 diesel and I find 5th is too low for motorway cruising.
Really? my 07 is getting under 40mpg during the last couple of months. In the summer it's under 50mpg.I have to say my 5 speed 2008 box was far better geared than my 2016 diesel 6 speed box, and would have a 5 speed Kia any day.
The 6 speed to me is all wrong, plus my 2008 was better on fuel.
I disagree. 6 gears on a manual are so much better. If the gear spacing is too great then you often can't find a good gear on country roads. I I really don't like the engine revving to high on the motorway. Lower revs are quieter and tend to use less fuel.If you are thinking of a box transplantation then you should check the gear ratios to see if the 6th gear is actually a higher ratio. More gears does not necessarily a mean higher top gear ratio.
Personally i think 6 gears are too many for a manual car for every day use, there is just too much gear shifting required. 5 are enough, otherwise automatic.
If your top gear is too low for your motorway use then larger diameter wheels/tyres would be an easier option.