Yeah you have to do both. It doesn't have to be too expenisive buy labor will cost you. You can find some 3.73's on accuautoparts.com for about 140 a set but you'll have to buy probly 2 master install kits as well there about 75 bucks a piece and install will run you between 450 and 900.. So I'd say you'll be looking at around 1100 bucks. Hope this helps :great:
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