While the 250/270 classes remain popular in some areas, as here in central PA, they can have an intimidating engine program, especially on the beginning side of the engine setup and maintenance learning curve - it's more labor intensive and more expensive than running a 600, unless you build your own engines and have the tools and knowledge necessary to take apart and reassemble a built up crankshaft. However, the biggest drawback in the long haul is going to be engine availability and cost, as the EPA has essentially killed the 250 two stroke water cooled motocross class from which these powerplants are derived. The hardcore competitors reply that the aftermarket will fill the gap, and they are right, but only at a price, and that price is driven by high production costs due to low volume due to small demand. The motocross industry has converted to larger displacement 4 stroke engines, so the 250/270 competitor is slowly being forced into the situation the quarter midget community found itself in many years ago, before they opened their rules up to the 120 and 160 Honda engines. Quarter midgets were powered (by rule requirements) by a specific flathead engine (not a Briggs; might have been a Continental) that came into existance during WWII to power small portable generators and things like that, that the military commonly used. For years they were common and cheap, then the supply slowly dried up as other engines came to be use by the military and civilians for these products. At the height of festivities, a rebuilt rulebook engine for your quarter midget cost $6000 IF you could find one to buy, because of supply (no current manufacture and none left in the surplus market) and demand (much bigger than supply, though the class was dying). And we are NOT talking 2010-2014 $$ here; in today's dollars, those engines would be over $10,000 for what is essentially a smallish lawnmower engine. That is where the 250/270 class is headed right now, slowly and inexorably, and if the rules structure is not revised (which would mean changing to rules using the current larger displacement 4 stroke engines now used in motocross racing in place of those 2 strokes) at some point, the competitive 250/270 class engines, which already cost more than a 600 engine to buy and maintain, will price the class out of existance, as almost happened with quarter midgets. The upside is that the chassis need not change, only the engine mount plates, so the cars presently out there would still be useful and competitive, just no longer powered by a stock or stroked and bored 250cc motocross motorcyle engine.