The 51 is a completely different animal than the inline 4's. It has a ton of torque but not alot of horsepower. In the straights the jap bike is gonna come right around you but in the twistys its 51 all day. The 51 is a race bike for the street, well not really for the street but thats where most people ride them. Its got a hard seat and hard suspension and its big and its heavy and it runs HOT. But get it out through some turns and its a GREAT bike. You definately need to ride one before you buy cause their not for everyone. Good luck with your purchase.