Black - hahahahaha Harbor Freight Tools is the way to go for most any machining/tool needed.

(My dad was a machinist and that was our Sunday stop after IHOP!.. LOVE IT!!!!)
I have not swapped out the suspension components in the 05, but when I did in the 98 it made a world of difference and Eibach was the way to go.
9 months ago, I would have said NO to the Eibach. Our discussions with their Reps from Marketing and Engineering personnel was less then impressive. They lacked advanced planning and track tested engineering for the S197 3-point rear architecture. Eibach was not prepared for a true aftermarket coil-over design. Most participants in the V-6 tech section found that HR was well ahead of the game and preferred their products, even though the cost was more than Eibach.
I was recently checking into the various suspension packages and it appears that Eibach has yet to catch up in a true-to-form coil over AM product.
In the end, if you are looking for a moderate drop and a true quality replacement for the existing coil over rear design (and do not want to sacrifice the handling and ride quality for a DD) HR would be the way to go.
I would like to hear additional feedback from other participants who have swapped F&R with a street/track kit with a drop rate of => 1.5".
Either way, Camber/Caster kits and high performance struts and shock absorbers matched to the characteristics of the replacement spring sets would be a must.
Having owned 3 Stangs, I have always felt that although Ford COULD engineer an advanced suspension design from concept to production, it would rob us "modification junkies" of the quest for the perfect individualized suspension. What I like, is far from what Black may like, but in the end, I prefer being able to swap it in a weekend, versus taking it to the dealer or a modification shop to do it for me. ASE labor rates for a swap out on a Ford are too high. It is a fairly easy do-it-yourself modification that makes every bit of difference if you do your homework and pick a package that will fit your individual needs and wants.
Good Luck and enjoy the ride.
Jennifer