On the shipping, they will change the shipping location after you add another item. I understand the distance on pricing, but they do ship "weird".
Let me explain, a little better.
Select a set of spark plugs for X year X model X engine, go to checkout and it ships from location A.
Continue shopping.
Now select/add a set of spark plug wires for the same, go to checkout and it ships from location A, the spark plugs now ship from location B.
Delete spark plug wires, now the spark plugs ship from location A, again.
Cap and roter, ships from location D.
A cap and roter kit, (same parts) ships from location A. Normally $2 more, but the shipping is cheaper which equals a better/cheaper overall price.
This is my complaint/concern with them. I see what they do, and check all items and tweak items for the lowest overall price. Usally I pay more for a higher quality part, for a much less shipping price.
I paid $10 extra on just the parts on my last order, but saved about $25 on shipping (-5%).
To me that means I paid more upfront, but paid less total.
Beer thirty.
edit: Just trying to save everyone money.