For real handling improvements on curvy canyon roads, what would be more effective?

Lowering springs (from _____?)
OR
the larger rear anti-roll bar + the front and rear lower frame braces from UltraRacing (available from Throwdown Performance with free shipping)

All of the above & then add poly bushings to your list.

Whose springs did you go with?

Whose shims did you use to correct the alignment?

How long have you lived with all this yourself?

I have Arden springs all around. The only shimming involved the rear camber & we used factory shims. I have had the springs for about 6 years as well as the poly bushings, the Ultra Racing braces have been on about 2 years.

JgaXkr,

How much difference did the Ultra Braces make? Did you get all three(3) or what? I am familiar with top brace when it comes to a front wheel drive but that is about it.
I measure rear anti roll bar at 19 mm on my car(2006 XK8). The Ultra roll bar is showing 20 mm. I am wondering if you know what your rear roll bar measured initially. This seems to be info not floating around handily. I wonder about changing this piece out.

Mike

I think the rear sway bar is smaller than that. If I remember correctly the rear bar is smaller on the coupe as well. I can measure my old one as it is sitting on the floor at the shop. My car is an XKR so the top brace would not fit my car but I still think it makes a small difference.

JgaXkr, you were right. It was smaller and about 17.5 mm diameter. It helps to measure in the daylight when you can see everything better!