[gfong]

Here are a few Canadian sites:

http://www.steeda.ca (highly recommend)
http://www.mustangtoystore.com/ (DaSilva Racing)
http://www.performanceunlimited.ca/
http://www.seanhylandmotorsport.com/

USA sites that I have purchased from and have never had any issues with them from online sales!
http://www.mach1performance.org/default.htm (highly recommend)
http://www.classicdesignconcepts.com/
http://www.americanmuscle.com/
http://www.summitracing.com/
http://stores.ebay.com/Jons-Mach-1-Fun-Store
http://www.accufabracing.com/
http://www.jlttruecoldair.com/
http://www.moserengineering.com/
http://www.taperformance.com/rearend.htm