thanks for your feedback guys.at the mo i have 155 bhp on a normally aspirated 1.9 cvh in a mk 2 xr2(single carb)(standard xr box almost dead)but am getting motorbike carbs by boggs bros this summer.this will take me to around 180 so think i will go with the standard rs box.need a good used one though(no crap),if any one knows of one .