So decided i need a new stem, 31.4 bars, and a slight up rise, but how are they measuresd from the centre to centre or overall length, and will a short stem make any difference to climbing or descending.

Also why the huge duiference in price for basicly 2 clamps and a bit of pipe.

Centre of bar to centre of steerer tube.

You pays your money and takes your choice – stiffness/finish/quality/blingness/branding

recently switched from Thomson X4 70mm 0deg to Raceface Turbine 60mm 6deg (£42.50 from Merlin) and the difference is noticeable when defending, no real diff when climbing.

check the Haven Stems on Merlin now, some nice deals