I'm also looking at replacing my rear LCAs. Hoping this will improve grip off the line. I'm not really sure what brand to go with or how much difference I'll get. What will this do to the ride quality? Any difference?
LCAs alone will not help grip off the line "that" much. They will improve the overall performance of the rear-axle, in terms of stability, traction, wheel-hop, and give you a more precise "point and shoot" feel when going WOT.
I typically recommend LCAs before just about anything else, for the majority of my customers, simply because they help eliminate the ever-so-dredded wheel-hop symptom which occurs commonly with the S197 Chassis.
In terms of ride-quality, they will not really affect it too much. What they will do is, transfer a little more noise from the outside of the car, to inside the cabin. This noise can be described as a slight whine, or "whirring" noise that is the combination of axle gear sound + road noise. This will happen with ANY LCA on the market, assuming that they utilize higher durometer bushings that the factory pieces.
If you have any other questions pertaining to suspension, especially BMR Suspension components, please don't hesitate to ask.
You are absolutely correct about what the lowering of your car has done to your traction. The primary piece of the puzzle, which is part of that package, are the LCA Relocation brackets. Those will do wonders for you, in terms of maximizing the cars potential to achieve traction both in a straight-line and upon exiting corners.
The package that you linked to, is probably one of the most popular packages that we sell here at BMR Suspension, and we build suspension components for 15+ different vehicle platforms. Like they say, the proof is in the pudding.
If you have any questions, let me know!