Outer Limits 4x4 Board

just fitted 33 tyres to mav,how will this affect my actual speed reading will the speedo be out by much?

Mine is 10%, so at 100 Im actually doing 110

With 33 inch tyres your speedo will be 5% out.
You can correct it by changing the gears in the speedo that are available from nissan.
There is also a calabration screw behind the clock face just above the where the speedo needle sticks out.
marks also sell a adapter kit

gu with 33's my speedo is dead set spot on..! from zero all the way through.
this is according to the tomtom.
i cant imagin the gps unit being out??!!
tried it in dads stock gu and at 100kays your really only doing 96.
cheers