Lil4X
Elio Addict
As to motorcycle helmets, in winters in the Texas Panhandle I'd wrap a towel around my neck and tuck it into my leather jacket, leaving one end free to stuff under my chin and into the bubble shield (long before full-face helmets). The leakage around the snap-on shield whistled a bit at highway speed, so I taped it up. OOPS! Without ventilation, the shield fogged up almost immediately, making for an interesting bit of one-hand driving while I tried to yank that towel out of the shield and clear my visor. No, I found they leaked for a reason. 
As to soundproofing, you can go overboard (!) with that too, as I proved on my boat. Spoiled by the quiet of my new Suburban, I decided to remove the engine box from my 24' cruiser and line it with 2" fiberglass insulation secured by hardware cloth. It worked great, as I lined not only the box, but the transom and stiffeners that ran from the box to the transom. I did a little too well. First, I discovered I couldn't tell if the bilge blower was running . . . so I installed a pilot light. My bilge sniffer/alarm worked fine in the event of a gas leak, but I had to know I'd exchanged the air in the bilge properly.
Then I turned the key . . . I could barely hear the starter, but I couldn't hear that 351 Ford catch and run AT ALL. Well, I learned to open the "sniff port" at the front of the engine box, normally used to smell for the distinctive odor of gasoline, but now with all my fine "re-engineering", reduced to the role of admitting the noise of the idling engine to the cockpit when starting. In open water this was especially necessary because the slap of waves against the hull would totally mask the soft burble of the underwater exhaust.
A bit of a pain at dockside, but it was really quiet underway. Of course if you wanted a little noise, you could firewall the throttle and trim out the outdrive to get the exhaust closer to the surface and steer with the trim tabs. It cost a LOT of fuel, but it put on a nice show with the racket and rooster tail.
I've promised not to be so irresponsible with the Elio.
As to soundproofing, you can go overboard (!) with that too, as I proved on my boat. Spoiled by the quiet of my new Suburban, I decided to remove the engine box from my 24' cruiser and line it with 2" fiberglass insulation secured by hardware cloth. It worked great, as I lined not only the box, but the transom and stiffeners that ran from the box to the transom. I did a little too well. First, I discovered I couldn't tell if the bilge blower was running . . . so I installed a pilot light. My bilge sniffer/alarm worked fine in the event of a gas leak, but I had to know I'd exchanged the air in the bilge properly.
Then I turned the key . . . I could barely hear the starter, but I couldn't hear that 351 Ford catch and run AT ALL. Well, I learned to open the "sniff port" at the front of the engine box, normally used to smell for the distinctive odor of gasoline, but now with all my fine "re-engineering", reduced to the role of admitting the noise of the idling engine to the cockpit when starting. In open water this was especially necessary because the slap of waves against the hull would totally mask the soft burble of the underwater exhaust.
A bit of a pain at dockside, but it was really quiet underway. Of course if you wanted a little noise, you could firewall the throttle and trim out the outdrive to get the exhaust closer to the surface and steer with the trim tabs. It cost a LOT of fuel, but it put on a nice show with the racket and rooster tail.
I've promised not to be so irresponsible with the Elio.
Z
