what are the main differences between them, besides the engine size. Does the mpg differ because from the 600 to 1000, its only$2000 more

well l no tht the gsxr 750 is alot better with turnings but unfortunatly thats all l really no. Sorry

l would think the 750 is adequate for most road use, you will have a job besting that beast!

You r correct, the only real difference is the engine. They r nearly identical in size, weight, braking, handling, the difference is the power & gas mileage somewhat. If u r concerned about gas mileage u probably should not be buying a race bike as they have high compression engines designed for maximum power. A Suzuki SV 650 will get 5+ mpg more then a GSXR600. If this is ur first street bike l hope to god u only get a 600cc bike as the 1000 will wheelie in several gears. Yes, the price difference now maybe only $2000, but have u called ur insurance company? Often the cost of insurance will double on sportbikes over 650cc, u will need to call several agencies as prices will vary widely even on the same bike. l have a Kawasaki Ninja ZX-6R, great bike, but Progressive wanted $1700 a year, called Geico & got same coverage for $525 a year. l have Erie Insurance for my cars, but they wo not insure sportbikes.