mid arm or 2008 kit ?

[noby]

ok so i got me rb5 up and running,had some fun ,now its time to get more seriouse.i got the zx5 silver springs on the front, thought that will do for a start, now i need to sort the rear out.do i go for the whole 2008 coversion kit or just the mid arm,by that i mean longer dog bones, 54mm shock,and longer arms.some say the lower tower/shorter shock may not suite british tracks.