01 smoking and oil consumpton


looking to buy an 01 busa in pretty good shape but it smokes white smoke on excelaration and decelaration.im thinking valve seals or rings.now if you drive it at slow speeds or wot it doesnt burn oil,but if you drive it at a a steady 7,8000rpm it burns oil,weird.i can get it cheap,what other yrs motor will fit if i have to change it.
More likely the valve seals. If it were the rings it would smoke all of the time.
thats what i was thinking.should have been more specific,whitesh blue smoke,it is oil smoke i followed for 100miles and watched it.does the engine have to come out to do seals?