The x73 is nothing like the RoW suspension. It is the porsche designed, competition suspension, consists of struts, springs, and motor mounts. It lowers the car a full 30mm (RoW is -20). It is significantly stiffer than stock or even pss9s. I had it on my c4s and loved it. I wish they made it for the 997tt.
Ruf springs are made by HR and are very stiff as f1 and Doug pointed out. I currently run the gmgs, which are very similar.
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H&R springs are great but my problem now is too much neg camber. Did anyone here have to get camber links to correct bad camber to get it back to stock spec?

 

I'm looking at getting some lowering springs as well. How do you like the H&R springs? I've been doing some research and asking several sources so that I get the car lowered the right way. What I've found is that in order to give the car a proper alignment you need to have rear adjustable toe links and rear adjustable upper control arms. This will certainly help with inner tire wear on the rear tires and give you the ability to get the car aligned to the specs that you want based on how you drive the car. I think it is probably a little less important to have adjustable control arms in the front but certainly will help as well.

I am looking for a deal on some adjustable upper control arms and the right springs to get. I already bought myself a set a of GT3RSR adjustable toe links.

 

All you need is the adjustable rear toe links with the springs. The upper control arms aka dog bones are gravy. Great if you have them but not necessary, in fact a lot of guys are going back to the solid upper control arms for track use go figure. The front LCA will allow you to a lot more negative camber with shims (>-2), but you can achieve -1.5 just by lowering the car.

 

Just be aware that they are noisy. If you are used to the relative quietness of the OE suspension, you will be in for a surprise. I've got the AP adjustable control arms and dog bones in the rear and don't like them at all due to the
noise which is a result of the lack of rubber in the ball joints of the adjustable parts. On the ends of both the adjustable links and dog bones, there is nothing to absorb the shock and noise transferred from the road to the car through the suspension. In theory, the handling is probably improved at the limit because there is no rubber to compress and deflect thus changing the suspension geometry but at the expense of noise and harshness transferred to the cabin. If you frequently track your car than its a fair trade off but if you mainly drive it on the street, to me it's more of an annoyance. I would prefer to accept a tiny bit of give in the suspension components in exchange for a quieter "clunkless" ride. I am probably going to put the OE links back on my car and raise the coilovers just enough to allow me to stay within limits for the camber and toe on the rear just so that I can get rid of the harshness of the AP links. I wish someone made some adjustable links that employed some rubber isolators via the OE design.

 

Be careful of those AP links, I believe there have been some durability issues with them. As I said a lot of guys are using the solid upper GT3 control arms with adjustable toe arms.I like the Tarret because they are based off a Porsche part, made in Germany.
check out www.renntrack.com

 

beautiful set up !!