No a different diff ratio won't magicaly give me better acceleration, but it will lower all the gear ratios and bring them closer together. Top speed will be slightly lower, but still about 200km, but the gears should be closer together (Less rpm drop when you change gears). When I use my 305 cams, I expect the powerband will be narrower so I want closer ratios for the track. A low ratio diff is cheaper than a close ratio gearbox!