I think the biggest advantage of a roller is they can have a much more aggressive profile...they can snap the valves open much quicker than you can with a flat tappet.I'm no cam guy I let the experts pick mine for me...the main thing is be completely honest with them in the description of the car/engine and your application.Give them as much ACCURATE information as you can. Especially the compression ratio...don't guess, KNOW what it is, or will be. JUST MY OPINION