I've gathered the parts needed to install a rear anti-roll bar in my '06 DB9 Volante...except for Part #701154, the four "SCREW M8x21 FLG HD DUO TAPSITE" flange screws needed to attach the two "straps" or brackets that, with their bushings, hold the bar at the rear of the car.
Nobody - including the Aston Martin factory - seems to have these in stock. While the thread isn't listed, I'm assuming that there's nothing special about these fasteners, and in a worst-case scenario I could even go with washers on regular hex head bolts. There's also nothing listed about material or strength.
Does anyone have any wisdom or expertise to lend?
Thanks!

 

Remove one of your front bar mount bolts and match it up at a good hardware store. And yes you may have to use proper washers to match the contact area of mounting.

 

I just bought M8*25 Zinc Plated High Tensile Flange Head Bolts from Ebay.

Originally I thought that there is nothing behind the mounting bracket so the 4mm extra length won't touch or harm anything, and better than being 20mm and slightly too short, however the DBS because of its 4mm larger anti-roll bar (that I've now fitted front and rear) has a 2mm spacer plate on the rear still uses the same 21mm bolts so 20mm would be fine on an early DB9 (25.4mm diameter) sway bar.

 

Thanks. Settled on zinc-plated 8mm 1.25 x 25mm 8.8 grade from Home Depot until the official fasteners come in. They're not as hard as I'd like, so I'll check them regularly.