It seems the generally consensus is the GTSpec lower tie braces are very good for stiffening up the frame on the sedan. I'm looking for feedback from sedan owners who have installed the lower tie braces regarding the affect on ride comfort. Another member impled it kind of undid the "independence'"of the independent suspension. I definitely would not want to be riding in a car that feels like it has solid axles.

 

Absolitely no negative sideeffects. Rear bar cannot possibly "undo' rear independence, since it's mounted on frame and not on moving parts.
Go for them! You will love how composed and "tight" car will feel.

 

Actually, supplementary bracing can make the car just a little bit more comfortable if you're riding on a stiffened suspension (i.e. coilovers). the reason for this is that the bracing prevents the frame of the car from flexing. the stiffened chassis forces the coilovers to take the brunt of the force. Small road imperfections will be dampened by the suspension as opposed to the body.

 

I have the lower front tie bar, wanted to install the 2 rear bars but the Stillen exhaust is in the way. I'll repeat what's alreadt been said...there are no negative side effects. It has no bearing on the suspension, only stiffens the chassis. If there is a down side for the front bar, it's that the oil drain plug is a little more difficult to access.