It's been a while, 1QwkSport2.5r. We've finally formed up a motorcycle chapter, which I have been busy with,
http://cmaswr2.org/NM/BLACKWATERDRAWGOSPELRIDERS

Yes, I've heard a lot of good running diesels, they are more economical due to the efficiency of the cycle for small motors and because of and lack of nitro that they don't have as loud a pop. Where I am at currently, we fly in a city park outside city limits where the only neighbour is a farm house a quarter mile away, which now vacant. Noise concerns are very few for the moment, and as long as the other modellers don't object one is good to go. Some fly the big stuff, and so they are used to being a little noisy. Due to construction of high voltage transmission lines bordering the property, the city will move us to the other side of the park. In that case, if closer to picnickers, we then may require mufflers for the larger stuff. Except for CL and small RC stuff, we've been using mufflers anyway.