The most oft mentioned is autoahausaz.com since they clealry state is the part is OE equivalent, and clearly state is a alternate part is non-OE, and they choose to stay out of the too-cheap-to-be-true non-acceptable poor quality parts game.
Of note, on Bosch items like a MAF, where lots of auto parts retailers and a good number of internet sources play rebuilt and no-name games, autohausaz has been very very upstanding on what they sell.
A $50 order gets you free UPS shipping, and they ship out same/following day. Good company.
On some maintenance parts amazon.com can sometimes lead to a-hair-better-pricing, depdning on the freight policy for a particular item. Example can be like O2 sensors, when you know the correct Bosch part# you need.
Autohausaz.com is the first place I look for parts, and usually the last. Excellent customer service, great prices, fast shipping, all you should need.
Caveat for ANY online vendor: their parts catalogs are not perfect. They may not list all of the parts they have for your car, or they may list several alternative parts and that may not let you know which one you actually need. For example the O2 sensors can be tough to figure out. So hit the manufacturer site (such as boschusa.com) and use their parts finder to locate your part number(s). Then search that number on the vendor site. Another example: this is how I found a Hengst oil filter for my car; autohausaz stocks it, but doesn't display it as an option if you look for an oil filter kit.
I have also used and can recommend importec.com and rmeuropean.com. Importec sells a lot more aftermarket (non-OEM) stuff, so be forewarned.
I have used several others, but would only recommend the ones listed above.
If you need dealer-only items, and shipping costs are not too bad, then check with duvalmotorcars.com. Duval is an MB dealer in Gainesville that sells at a pretty good discount from suggested list (most dealers charge more than list for parts). If it's a thirty dollar part it's not worth the effort since shipping will eat up your savings, so plan accordingly.
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