:iagree: I would rock the holy bitch out of that brace!
That sort of brace would strengthen things but it looks like it’d also be a lot of weight. The main problem I see is that you’re not tackling the weakest link, which I assumed we were talking about, which is the front end. Plus, the mid section of the car will get braced with a roll cage anyway so it seems something under the car may be overkill when you consider the weight.
I really wish we had that document because I thought I remember it saying that the GSR was beefed up in the front, I thought it was the same as the other models from the firewall back.
Well DAMN you Colin! Find said document! 
I really think some of these braces are too much for the goal at hand. I think with a decent upper strut bar (2pt Neuspeed, maybe even a 3pt. But as said the firewall is kind of flimsy there) and maybe even a lower tie bar would stiffen up our front ends enough. Add in a set of those fender-braces for added resistance against torsion/flex, and we’re golden. But then, this is purely speculation as I don’t have much of any track experience.
Well to get back to the frame rails and reinforcing them I think it’s at least worth a try. I mean lets say it doesn’t make a dramatic difference then you really only added what? Less than 10lbs to your car. As well as making a nice shield from speed bumps!
That brace pictured is going to weight WAY more than 10lbs. I’d guess each side weighs 20lbs. But really it depends on the gauge used. And it won’t guard much from speed bumps because your exhaust hangs lower than the frame rails…
The actual braces alone weigh about 13lbs (14guage stainless steel); that does not include the “x” braces ( which weighs 15lbs) as pictured in the second picture I posted, so altogether close 30lbs, so yea it’s a bit heavy but it does have positive results.
Details can be found here, but again this is for a MIATA.
http://www.flyinmiata.com/index.php?deptid=4538&stocknumber=13-69010
Like I said, I’m just throwing the idea out there and granted it doesn’t resolve the front end issue, but again it’s something to toy around with…
I remember on tnd2gen/Pat’s car, in front besides adding fender braces, he also fabbed up reinforcement bar in the front end, parallel with the rad support- I’ll try to find pictures of it since his personal site is no longer online anymore.
Yeah Miata is a whole different story since its a convertible. The weak points on that car are hugely different. Not saying it wouldn’t help on our cars, just that there’s really no point unless you first tackle the weaker links.
Pats bar in front I don’t think stiffened up much, not much more than the OE bumper support would really. I’m not sure why he installed that bar actually. It may have been for reasons other than rigidity, especially since the direction it worked in really wasn’t as important as others. I know he had his tow hook welded to it, so it could have been installe because the car didnt have the oe bumper support - anyone know if the Canadian cars still had the US spec bumper support? And no offense to Pat (he’s a personal friend of mine) but did you see his front crossmember? He hacked that thing to pieces for weight reduction, it looked dangerous. Luckily another friend of ours convinced him to remove it in favor of a Full Race traction bar.
Believe it or not, maybe a year ago i emailed Pat about chassis reinforcements, i dont wanna post the emails without Pat’s approval (not that he’d probably care, super nice guy). That being said ill post a few things said. My question to him was which points of the chassis are the weakest and have the most flex. His answer was “The front and rear pillars and the entire front (ahead of the fire wall). Good to tie up the pillars to a solid roll cage. Also good to tie up the front strut towers to the firewall (or roll cage is best) which requires to tie up the lower front (ahead of the rad).” Also "The trick is that when you tie up the upper strut support, the energy goes to the weakest point (the front), which is why you need to keep the front from twisting. I made a chromoly front chassis support to balance out the stiffer upper strut support. " Well i hope that helps, atleast as far as the bar. Unfortunately i have nothing about frame rail bracing, But my guess is it would probably be cheaper just to cage it. However if you were dead set on frame rail reinforcement, i think itd be cool as hell myself, especially like the ones pictured.