What are your opinions on this?

Have a lot of stories of the six speed box been made of chocolate etc is this true?

Went on a eco run today, Dubiln to Cork and back. 27mpg over all, and I pushed her on a few times. She is a little high in the rpm range for cruising imo. What I'm debating at the moment is a 6 speed box to counter act the higher ratio diff, its only 3.15. Would an evo box mess all the gear ratio's up?

ORRR stick with my box, live with the high revs and drive the 100k odd miles it would take to justify the expense of a six speed?