I installed the Hfc's with help....
If your doing it by yourself try getting some help,
I used 3/4 high impact socket 14 mm, high impact universal swivel 3/4,
and 3 long extensions so they end up high enough clearance to add a 3/4 to 1/2'' adapter high impact also with a 1/2'' ratchet with a small extension pole for leverage to break it loose
one person on the top to slide the extensions down to the bolt and, another on the bottom to guide the socket in place and to hold it in place while the top person breaks it loose.. I used high impact universal and socket due to breaking too regular craftsman sockets.. use some Wd 40 or liquid wrench penetrating oil,
There's extractor kits for stripped head bolts.. or a muffler shop can torch it off and replace with a temp nut and bolt..
there is also a DIY on the Install with some pics
http://www.the370z.com/diy-section-d...c-install.html