I've used
http://www.oemmitsubishiparts.com/ for the last several years - their prices are comparable to Mitsubishiparts.net but their shipping has always been a little cheaper. They are in Texas so your results may vary.
I used to use Walker Renton out of WA state way back in the day, but I think thety gave up their franchise awhile ago.
Since then I price check all the sites including those mentioned above, but parts.com always seems to come out ahead - at least on parts pricing. I think I recentlat had some specialty bolts and trim clips on order - stuff that didnt even make up a lb. - and they still ended up charging me $11 for FedEx Ground. Apparently $4.95 small USPS flat rate isnt an option. That and anything they order has to go to them first - no 3rd party drop shipping. So yeah no wonder you have to pay twice the avg price on shipping!
All kidding aside, their OK - just hard to get a hold of outside the internal messaging system.
That and another plus is they can order parts from just about any OEM - incl. Porsche accessories! <img src="/forums/images/graemlins/cheers.gif" alt="" />
Another good pricing example... I needed a new exhaust manifold for my 90 Max 2.4L - no one on the boads volunteered theirs so I shopped it around... local Mitsiu dealer wanted $320, other online OEM dealers charged about $220-250. Didnt wait to check their freight rates, but Parts.com's price: $152 + $40 shipping for this and a few other misc parts.
Shop around, especially if the parts get expensive.