There is almost too much room between the edge of the headliner and roof of my 2014 hardtop coupe, that I had to tape the wire in multiple spots for my bluetooth mic to get it to stay hidden in the headliner. The driver side a-pillar pulled right out for me being held on by only a couple of clips. It should be the same, but I am not 100% sure if you are referring to installing the radar in your 2011 convertible.
Eibach Pro Kit, Dual Flowmaster 40 Series Axle Backs, 18" Milanni ZS-1s, 245/45R18 Falken ZE-950 Tires, Smoked Front Marker Lenses, Limo Tint, Pioneer Double Din, Alpine & Kenwood Speakers, 12" Kicker CVRs, Alpine Amps, AM Paint Matched Side View Mirror Caps, LED bulb conversions everywhere
, more to come... need to sell OE wheels/tires and suspension first.