Would Thule roof bars for an E36 saloon fit an E42 saloon?

Oops-- I meant would E36 roof bars fit E46 saloon?

NO. Here's a subject I definitely know about. An E36 requires the Thule #400 foot kit as well as the #145 fit kit. An E46, however, will require the Thule #753 BMW specialty carrier kit. Beyond either of these, you will need the horizontal load bars, and then the trays/carriers for whatever outdoor activity you're in to. For more info, check out www.rackattack.com, or go to Thule's website.