The M20 original (115 kg) is Uni rigged with a clean concept which means snail for the spi, internal halyard for the spi, carbon rig, cascading blocks and so on. This gives LOW windage and excellent upwind speed that no other M20 configuration can match! Most M20 are uni rigged, there are a couple of versions with jib, some with a jib bridle, stainless rigging, big fat main sheet block which means increased weight and increased windage!

The sloop is a "high lift" device and is good for downwind and reaching, but suffers on the upwind. The biggest gain if you added a jib to an A-class would be downwind, the upwind would probably be worse due to the increased windage and drag.

If you need more info on the sloop vs uni try searching in the forum.....

/hakan