Maybe I should have test drove a convertible instead of the coupe but now that I have it one day I am noticing a distinct difference in the rear stiffness. It seems everytime I hit uneven road the whole rear shutters. I am guessing this is normal, and if so what would be the best thing to lessen this. I am not as concerned about handling as I am about stiffening the rear to stop the shuttering. Thanks

 

There is definitely a difference in the body stiffness from the cabrio to the coupe - but I don't find it alarmingly different. I've had a metal on metal rattle when going over bumps since the car was new from the right side of the top, around the area where the rear window meets the top. With the roof down I don't get any such noises, and the body only "shudders" when I encounter very large bumps, that would make pretty much any car shudder.

I brought my car in yesterday for its first ever visit to the dealer (after 6k miles) and the head tech tightened the roof at all possible points and the car is completely different. I've gone over quite a few bumps that would ordinarily cause the annoying rattle, and now it's silent.

 

can you fit a rear strut tower bar on the cabrio's?

turn up the stereo?

 

This is really funny but what I thought was rear end rattle was really vibration in the cowl (front end) of the car. I was looking in the mirror every time I felt it and saw the rear seats shaking but it really was the mirror! So what is the best solution here, front strut bar, the m7tuning USS, or coilovers, or new springs. I get a different opinion depending on which sales place I speak to.

 

I drove a convertible for two days and I can say that there's a definate shimmy & shake of the chassis I don't much care for at all. I'll take a hard-top anyday!

 

I'd like to minimize this as much as possible as well - I've thought about the M7 USS - I've heard it does wonders for the handling ability by reducing understeer quite a bit. I've also heard that it works really well with an upgraded rear sway bar (I have the three position Alta bar set to its most agressive setting). I worry though, that the USS system might cause other problems while fixing others - like more vibration making its way into the cabin.

If any cabrio people who've installed the USS can chime in, I'd be all ears!

 

I've heard from a few Cabrio owners that the USS system does stiffen up the chassis and ease some cowl shake. A strut bar is also on my list- after I upgraded power I'll occasionally get some front wheel hop if it's uneven or slick conditions under heavy accell that I think a strut bar would help with.

Coilovers/stiffer-springs on a cabrio is not a good idea: stiffening springs and shocks is going to increase vibration and stresses places on the chassis (why the cabrio doesn't have SS+).

I think that my car is pretty solidly put together, cabrio or not. Especially compared to any older or similarly light cars out there. I'm not rushing to install the USS or a SB, but it'll probably get done some time.