An open install will typically run somewhat cooler and is somewhat easier to install/ set-up ... An open install however generates for some more internal drag so its not as aerodynamically clean. If your engine is running well ( as in not spitting fuel and fire out of the business end on start up) .. you should be fine with an open install ... Only time i would go out of my way to seal up a fully bypassed set up is if you are looking for max performance and efficiency, or if its a really tight install and you really want to keep the turbine/heat/fire as physically separated for the rest of the aircraft components as possible. Also, if going with a bypass and using gas (propane or power max) make sure you have good airflow as a gas build up before ignition can "pop" pretty hard inside the bypass if you get too much gas (again, not an issue for most engines ...


~V~