Aluminum Lower Control Arms:
 

My Aluminum LCA's, they weigh about 2 lbs each with rod ends installed.

Rod ends at both ends ensure zero measurable bind or deflection.  The stock LCA's weigh about 4 lbs and many aftermarket LCA's weigh much more than that (some even more than double).  They are 1/2 unsprung weight so this weight is not definitely not desirable if it is not needed.  It is not.

Double Rod Ended LCA's ride too harsh for you?  Try Rubber in one end:

They are made from 1.125" diameter by .219" wall thickness 6061-T6511 Aluminum tubing from Coleman Racing Products.  They are about $12 each.  You want the 16" Trailing Arms.  This will give you LCA's adjustable for length from 19" to 20.5" while keeping  at least 1" of thread engagement on the Rod Ends (which gives you a large margin of safety for thread pull-out).  They come tapped with left-hand theads on one end and right-hand threads on the other end so they can easily be adjusted on the car with wrench flats machined in so you can tighten your jam nuts properly.

In case you're wondering, yes, these LCA's are strong enough.  LCA's see their largest dynamic loads in tension (hitting potholes, etc).  These are good to more than 26,200 lbs each.  The rod ends are only rated at about 28,000 so making the LCA stronger than that does nothing more than add weight.  Unless I chain my axle to a tree and push the car off a cliff, they ain't gunna break.  In compression they are good for 18,300 lbs each.  That translates to about a 0.6 second 60' time.  So they might not be strong enough if you're quicker than that (don't you wish!).

Yes, the F-Body aftermarket over-builds, over-charges and under-Engineers this stuff.

One note I should have made long ago on the subject of strength:

Three years ago I crashed at Seattle International Raceway.  Brakes failed (my fault) and I came in way too hot to 5a...went around and went into the hillside at track left backward.  I hit hard enough to bend my axle. 

But the LCA's held up fine.  They were strong enough to bend my axle  How much stronger do they need to be?.

A QA1 rod end compared with one supplied with the Spohn arms.

Please See my Rod End Update!

A few years ago, I started out with Spohn LCA's.  They were of decent quality but rather heavy.

The biggest complaint I had with the Spohn arms was the quality of the rod ends they came with.  When new, the ride quality was not bad at all.  There was simply an increased "impact" over small, sharp bumps (expansion joints on the freeway, "bot-dots").  But that was totally acceptable for a daily driver (for my tastes).

Unfortunately, within a few weeks I started hearing strange noises from the rear.  These noises got louder and louder until they became a metallic rattling sound.  Eventually it sounded as if I had a coffee can half full of marbles rolling around in the trunk.  That was too much.  I put the stock LCA's back on for the winter.

This was caused by clearances opening up between the ball and race of each rod end.  This allowed the entire part to rattle over the ball when installed, making the noise.  Upon removal, I could wiggle the ball back and forth in the body with my fingers (the way they aren't supposed to allow movement) on each end.

So, I decided to step up in quality when I replaced them.  I replaced them with QA1 Endura 2000 Series Rod Ends.  These are much higher quality than the old ones.  Not as good as a $100 end, but at around $30 each they are a good value (being about 10 times as good as a $15 rod end).

When comparing the two, the first thing you'll notice is the body of the QA1 is much wider (as you can see in the above pics).  If you move the ball sideways so you can look into the race, you'll see this allows the metal-to-metal contact area between the body and ball to be much larger than the others.  This spreads shock loads out over a greater area, reducing the stress put on the body of the rod end.  This will allow these rod ends to resist deformation that will open up the clearances for a longer period of time.

The second thing you'll notice is how tight the balls are on the QA1's.  Even when new, I could spin the balls of the old ends with the tip of my pinkie.  Not so with the QA1's.  You can move these with your fingers, but it isn't easy.  You really have to crank on them.  This exhibits the preload (interference fit) on the balls.  As long as that preload is there, they won't rattle.

The third feature of the QA1's that I believe is an improvement is their Teflon®/Kevlar® Self Lubricating Race.  The Teflon/Kevlar mixture is injected into the rod end after it is assembled.  It then molds to the shape of the ball.  It constantly lubricates the ball, as well as absorbing some the the shock loads.  The old rod ends had a "bonded teflon lining."  It resembled some type of fabric that was "stuck in there."  Upon removal there were chunks of the stuff actually coming out of the rod ends.  I don't think that will be a problem with the QA1's.

So far I have more than 5000 miles on them (about 10% of those track miles) and have daily driven with them for more than two years.  They still don't rattle.

You can buy the QA1's at Racer Parts Wholesale.  They're a little over $30 each.  Part numbers XMR-12 (right hand thread) and XML-12 are the sizes you need.  Don't forget to get a 3/4" Jam Nut (also from Racer Parts Wholesale) for each end. 

The cheapest way to get spacers is to make them as shown below.  You can get the Rod End Reducer Bushings Here.  You need the 3/4" OD, 1/2" ID ones.