I just did a quick comparison of my most recent RA order between my typical shopping places: RA, Summit, and Amazon.
Car and motorcycle spark plugs, air filters, belt, headlight bulbs, wiper blades.
RA's - $162 total - including taxes and shipping.
Summit Racing - $262 total - including taxes and shipping.
Amazon Prime - $301 total - including taxes.
That's quite competitive from RA.
On the other hand, RA's return policies/process pale in comparison to Amazon and Summit Racing.
The fact that RA does not have a customer service department that you can talk to in-person, is alone a reason to spend $100 more with Summit.
I understand that's how RA keeps their overhead to a minimum, but getting a wrong part, or needing help with your order and not being able to call a person just makes you feel helpless.