I did the the JBL’s also. I don’t know if you have the factory sub or not, I do and there was only a mild performance difference. Of course, if you have a faulty speaker, these will work fine for you. I also used the above video for installation without difficulty.
I seem to have that issue with the wind deflector installed which is understandable. What I find is without the belt strap in the holder, the passanger side buckle will slap against the door panel when the top is down as the belt gets caught in the air stream.
Like many here, I wasn’t looking for it when I bought my convertible. But now I wouldn’t by another without it. S and S and heated seats. Never going without heated seats again, lol.
S and S are great tools to have. I still turn my head and use my mirrors though.
No downsides for me. I installed the intercooler a few months before the tune and the car felt healther. Of course that's all butt dyno and its not a daily. After the tune car feels much better all around. No other engine mods for me. Tune and intercooler are all I need at this point.