Pick up one of those sets of six different vise grips while you're at it - you'll need them to remove the flare nuts after you've rounded them off with the wrenches hand-filed to almost be the right size.if you don't plan on using them every day Harbor Freight has i think a 6 wrench set for about $14 - made in China of course. they are shiny.
First, you don't need a set. Sets are designed to sell as much product as possible, including items you'll never use. The Snapon line wrench set is over $350, but on a Mustang, you only need 5/16, 3/8, 7/16, 1/2 & 9/16. I rarely use the 9/16 I have. I'd say get the 5/16 & 3/8 and 7/16 & 1/2 combo wrenches. It'll set you back about $50 for the pair, but these are the GOOD wrenches, none better, period.Read my original post. I want a GOOD set