Asteroids, Center of Mass and All That

[Agate]

With a thick stubby rocket and center-of-mass targeting, you can push as hard as you'd like without spinning out of control. In any case, you don't need big engines, you need specific impulse and fuel.

Of course, you don't need either when you let gravity and aerodynamics to do your work for you!

(Class B asteroid on high polar collision course, redirected to equatorial orbit using Munar slingshot, retrograde orbit changed to prograde with a high-apoapse burn, then aerobraked into prograde low Kerbin orbit. I think I only used about 150 m/s delta-V all told. Physics!)