I finally went to a huge fabric store and purchased some velcro to anchor down the mats. I was having very minor slippage, but enough to warrant some extra work on my part. Cut some velcro squares, and used a hot glue gun to affix them to the bottom of the Weathertech mats. Works really nicely.
I purchased a 12" strip, thinking that I would anchor down both front mats. However, only my driver's side has velcro anchors on the floor. Oops. So I have 2 extra velcro squares up for grabs. FREE.
First PM with your address, and I'll mail them to you.
2011.5 E90 Dinan M3, SS II, M-DCT, EDC, M Drive. Winter setup 220M w/ 255/275 Blizzaks
Performance Mods: Dinan St.1 suspension, exhaust, intake; TTPs; BPM St.II, DCT, servo tunes
Cosmetic Mods: OEM CF splitters, mirrors, center console, spoiler; Arkym CF diffuser; LUX; tint