[Moto-P]

Not exactly answering your questions in order but I will post what I just wrote in another thread.

If the adjustments you wish to make are beyond the range of adjustments of factory toe links, yes you will need additional aftermarket toe links. Most of the time, however, staying at within 40mm of ride height lowering, and for very minor camber corrections, you can use the factory toe links as long as LCA has a setting near that of the stock arms and are not drastically different to accommodate "Stance hard parking" configurations... For most racing duties, we only need to get 2~3 degrees of static camber.

Depending on the RCA of choice, the joints may be urethane, rubber, or hard ball joints. Anything harder than stock bushings will put progressively harder loads and impact on your suspension, and body sub-frame and uni-body structures. While going stiffer will provide a more direct feedback and retention of dynamic alignment on higher loads, simply going harder is not really always the best, and in fact rarely so on a part-time street driven car.

The ideal setup is achieved for many reasons, such as what sort of machine you are looking to build, what your mix of daily driving to racing is, if this is a mixed role car, and finally your driver skill and goals, tastes, and factors of how you drive it. Fully stiffened ball jointed cars will give lightning response, but it usually get VERY tricky for the drivers, and it also reveals more seriously, any flaws in the rest of the car. Ball jointed ends also cause great deal of wear and tear on not just the joint itself, but anything it is attached to as there is no give for alignment pressures of arms in motion, nor constant hits the suspension takes from the road. Only really true dedicated race cars need such level of precision, and even at that, it may be overkill. There are MANY other joints and arms in the suspension too, and if those all are not replaced at the same time, the single hard joint will adversely affect alignment as it moves too. I will not discredit the role of adjustable LCA, and yes for some applications it is necessary to build a race car, and in other times, to increase the durability on things like competition rally cars.
I had a role in designing the RS-R LCA we recently launched, as well as have been a test driver for Cusco versions very early in FRS inception. Both of them work very well for cars that need it, but it isn't frequent on daily driven Sunday racers to need that level of adjustments or durability levels. RSR LCA uses a high quality polyurethane joint for good pairing with stock parts mixed in the toe control as well as racing arms, and do have an optional ball joint you can purchase if the goal is a more hard core race car build strictly for tracks-and sub 200 UTQG tires. Cusco ones are ball-jointed and are proven in hardest of rally racing too, as the unit is also compatible for Subaru WRX's that see a ton of rally action all over. But like I have said, the Stock LCA are also, very good for this car and suffices for most non- high level competition casual track fun.

Best recommendation is to use a rubber or polyurethane bushing equipped LCA, that has some 'give' so that the rest of the suspension can work in unison, and to balance out the design of the rest of that car, that will NOT be seeing equal amounts of bracing, welding, gusseting, pinch-welding, and caging, to even out the rigidity.

Big beefy adjustable LCA isn't really too critical in this sense, as natural camber for FRS suspension statically is nearly 2 degrees at 30mm drop, and it's still within range to be happy on handling with stock LCA. So if you are doing it partly for visual appeal, by all means, but since you will be setting it very close to the stock dimensions for the most part in a daily driven occasional racer with street tires, it really isn't high on priority for most casual Sunday track folks. Best then to save the $500 to spend on better properly designed shocks, and tires that suite the role best, which will do wonders to handling of the FRS.
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Summary:

RSR uses high quality and precision fit polyurethane bushings on the LCA, and can also be ordered with ball joints if it is a race car build dedicated for the track on ultra-high grip tires. It is also equipped with triple range adjustment for sway bar stiffness end points, as well as triple mounts for shock ends to adjust the coilover stiffness and stroke range too. It also has dual position hub bracket so that ride-height, damping stroke range, and arm angle can be adjusted as well. It's been designed primarily from the FRS platform as RSR does not race a WRX, and RSR does race and supply a fleet of Toyota 86's for teams in pro-drifting, road racing, autocrosses, and other sports.

Cusco uses sealed ball joints, and is designed with maximum rigidity and durability that is born from necessity in their rally and road racing use on WRX's that see huge abuse. Yes the WRX and STI LCA are nearly the same dimensions stock so adjustable LCA can work equally well in FRS and Imprezas for almost all makes of adjustable LCA, which is what Cusco does, and does VERY well. (and anyone who is replicating their design)