The Post
I see both sides of this coin, and I too have much experience in the suspension world. Mainly Lancer Evo's after owning 4 of them and racing 2 of them. I could tell you stories. This Elantra though is no lancer evo, nor tries to be. Sure people want to mod a car, to make it "theirs" and that is cool, but there is only so much that can be done. What I can tell you is through every mod there are pros and cons. You really have to think about what your using your car for. Are you seriously going to push this Elantra through curves so fast to cause it to misbehave? 99% of the people out there no. Remember though, 99.9% of FWD cars are designed to understeer for safety reasons. Why? Its easier to come out of a understeer turn vs. an oversteer turn for the inexperinced driver. So IMO if you increase the stiffness of the rear the odds of oversteer are unrealistic. If you increase the front stiffness with the rear stiffness you may feel you are "blanancing" it out, but in theory your taking away from what your trying to get rid of. The rear suspension on this car is good, and has been used on many decent handling cars in the past. It does have some major drawbacks though and with the lack of available aftermarket parts for the Elantra it makes it dificult to make a valid choice. Its either "this" or "OEM" thats it. If you increase the stiffness too much in the rear WITHOUT the brace from SR then you may just bend the torsion beam and then your S.O.L. So if you lower your car with stiffer springs, use a stiffer shock, and roll on heavier, bigger aftermarket rims then this brace is saving the rear OEM beam from actually bending. If it bends beyond the threshold of stock (which isn't much considering what Hyundai designed this car for grocery getting not racing) then your looking at a VERY expensive boo boo. The brace would be cheap insurance. I am curious of the SR coil over system. The non adjustable dampening version. I am curous to who makes this set up, and how much stiffer than stock it really is? SR is charging a pretty penny for that kit considering your only really getting 2 coil overs, adjustable struts. The rears are fixed with new shocks and springs. Some more info on this set up would be quite valuable. Other than that, there isn't much out there. KYB rear shocks for those who want to stay stock would be a good start. Then go from there.
Just my ten cents...
Jeff