It's hard to argue with a store that actually offers good service to its customers.
All I can really point out is that you appear to pay a premium for their service. I looked at the Rogue Bear BA as a random, easy example. 1 euro, or $1 US from IWM for the same mini. With a quick check on exchange rates, it appears that 1 Euro is currently about $1.19 US. On most orders, that probably isn't enough to justify ordering from IWM.
On the other hand, for a rare order placed to use up a contribution to a FF project, you're likely to break even. It also doesn't hurt to send Speck or even Mike an email to ask if they'd waive or reduce the shipping cost on the order. If it's a large contribution, they might do it, though I will not make any promises for them.