When I did the EX conversion on my H1 I bought a caliper with master cylinder still connected by the original hose. This way there is much less chance of either being blocked up with crud or corroded as long as it is still a sealed system. (still rebuild both, and new stainless hose...) It also gives the advantage of ensuring compatibility. I also bought the matching clutch perch, both with mirror mounts and those nice dog leg levers, just gives it a cleaner look to me. I did have to pull 2 wires through the sleeve from the brake light switch (now on the M/C) to the connectors where the old switch is, but most will never notice.