I,ve got a disco transfer box fitted to my 300tdi 90 plus 7.50 tyres.It makes approx 25% increase in gear ratios,but then I spend a lot of time traveling the french autoroutes at 70-80 mph and get 32 m.pg on these trips at this sort of speed.Provided you start in 1st gear rather than 2nd, starting and accelerating is not a problem, in fact you can hold on to the lower gears for longer.and get better acceleration. On the long, straight, traffic and hold up free french 'A' type roads with a 59 m.p.h speed limit I often get 40 plus m.p.g. (with deisel at about 74.pence a liter) and get there quicker than I would doing the same distance on the m.ways and main roads in this country,where you do 70 for a mile or so then get slowed down to almost walking speed for miles. I also have recenty fitted recon disco axles and recently fitted 110 brake calipers on the front axle.braking does seem to be improved. (the transfer box increase gear ratios by about 12.5 % as do the 7.50 tyres.