Riiight. Leaded gas also helped engines preform much better, but the EPA got rid of it as an additive because it made a judgement call based on independent scientific research that the additive caused childhood retardation. The auto industry basically made the same arguments you do here, but the additive was banned anyhow, and childhood retardation fell precipitously.

"Up to one-third of the fuel delivered to the engine goes straight through and out the tailpipe without being burned. Second, lubricating oil is mixed directly into the fuel, and is expelled as part of the exhaust. Third, poor combustion results in high emissions of air pollutants as well as several toxic pollutants, such as benzene and aromatic hydrocarbons that the EPA classifies as known probable human carcinogens.

When compared to other emission estimates, a snowmobile using a conventional two-stroke engine, on a per-passenger mile basis, emits approximately 36 times more carbon monoxide and 98 times more hydrocarbons than an automobile."
-SEMA (non-gov't study)

"These engines create dangerous levels of airborne toxins including nitrogen oxides, carbon monoxide, ozone, particulate matter, aldehydes, 1,3 butadiene, benzenes, and extremely persistent polycyclic aromatic hydrocarbons (PAHs). Several of these compounds are listed as "known" or "probable" human carcinogens by EPA...

Two-stroke engines also discharge 25-30% of their fuel mixture, unburned, directly into the environment. Given current levels of snowmobile use in Yellowstone National Park, this translates into the equivalent of five tanker truck loads of gasoline being dumped along park roads each winter. Unburned fuel contains many toxic compounds including benzene, toluene, xylene and the extremely persistent suspected human carcinogen MTBE. Two-strokes are one of the largest unchecked sources of pollution nationwide. ... Snowmobiles are extremely, extremely dirty compared to anything else ... (s)nowmobiles are the worst there is"
-Senate Expert Engineering Testimony of Charles Emmett, May 25, 2000

"Two-stroke engine driven vehicles emit poisonous gases as these engines have very low efficiency to burn hydrocarbon. Hydrocarbon such as benzo(a)pyrene are produced by incomplete combustion. Bezo(a)pyrene is classified as a proven carcinogen which in process encompassing the conversion of normal cells to neoplastic cells into a tumour."
Dr. Jamal Anwar, explaining cancer proliferation in Dhaka, Bangladesh after introduction of two-stroke engine as major transportation mode

"In response to EPA's 1991 finding that recreational marine engines contribute 3 percent of all hydrocarbon emissions in the U.S., NMMA's member engine manufacturers accelerated their plans to aggressively develop new, cleaner-burning engines, which are both environmentally responsible, and consumer friendly. Research and development investment by engine manufacturers, creating entirely new lines of products, amount to an estimated $500 million. These improved engines will utilize four-stroke, direct- injected, and other low emission technologies for outboards and personal water-craft...

America's marine engine manufacturers have great confidence in the technical capability of our new designs. Because it is in the best interest of our manufacturers to have these new technology engines penetrate the market, as rapidly as possible, the marine engine industry will continue to extend every cooperation to CARB as it, and other agencies, develop new technical emissions standards and time-tables."
-National Marine Manufactures Association, on why it is phasing out two-stroke engine production, APRIL 22, 1998, Hearing of the Health and Environment Subcommitte of the House Commerce Committee

I've got tons more, but I know that some folks will never listen. I just wanted to put some of this information out there. Don't get me wrong; I loved riding two-strokes (especially dirtbikes) when they were around. Those engines are engineering masterpieces, putting out great horsepower and sweet torque. I sympathise with you. But I'm simply not willing to pay that huge environmental cost just to indulge my fascination for a dying technology when there are alternatives out there that are just as cool.