If it makes you feel any better you'll put $150 (at least) worth of radio gear in the plane too.

I feel like the extra money is worth it. Take care of the OS you'll have it for a very long time. It'll go through two or three planes easy. Looking at the OS75 on Tower Hobbies you can get a 91FX for a few bucks more (Nice engine.) It's over kill for the 4*60 but might be more versatile if you plan to build something a little bigger in the future.

I have an OS 46SF that's well over 10 years old and still runs strong.