Rigidity is key

If you look at the greatest advnances in new performance car development and what impacts performance increases is not power or fancy electronic chassis control systems. The most important and key factors which influences car performance are advances in body and tyre rigidity.

Body rigidity is a constantly overlooked factor of tuning with most people focusing on pushing as much power out of their engines or stiffening up their suspension and suspension links. In doing this they are forgetting about what all those components are connected to which is the body.

I have always been very sensitive towards how my car feels while driving. Whether it be excessive scuttle shake, too much flex in the strut towers or having a lack of feel from the rear tyres. These factors bothered me more than not having enough power to drag someone at the lights etc. For me what gives me confidence in my driving so that I can push my car is when I can feel what is going on with my car while driving.

Continuing on from my first boot brace rigidity mod. Next up follow forwards with the Nismo underfloor braces. These parts were released by Nismo in the early 2000's for the R32, R33 and R34. The R33's braces are reverse engineered from those developed from the R34 and then later released for the R33 as well.

The braces stiffen up the front area just behind the steering mounts. It actually replaces the factory BCNR33 front factory brace but also has extra mounting point to the rear of the body reinforcement and also bolts to the steering mounts.
Part number: 54422-RSR35
The lateral bar at the top directly replaces the factory brace and the bars coming down from that left and right are the extra braces which bolt onto the body reinforcements. In the case of the BCNR33 you will need to drill extra holes to bolt on.

Product number: 76440-RSR45 (identical to the BNR34 part)
 These replace the factory center braces with the Y arm part bolts straight to the rear member brace which joins the rear end to the center. 

Here I ran into an issue. The front brace did not clear the Fujitsubo equal length front pipes.

As can be seen this did not allow the front to be fitted so I drove around with only the rears while I ordered a front pipe which would fit.
In order to not have another misfit I took a leaf out of a fellow BCNR33 owner here in Japan Aki Itoh and his blog http://www.r33gt-r.com/search?q=front+pipe . As can see in his blog the Mine's front pipe is one which does fit so despite the price I placed an order for one. He also covers in more detail the specifics of the fitment of these braces. 

Regarding the Mine's front pipe http://www.mines-wave.com/E_09/CATALOG/SKYLINE_BCNR33_E.html is a part which is built to order so after placing an order it takes under 2 months. So those ordering from abroad keep that in mind when ordering.

Fast forward 2 months and it arrived. A beautiful piece of metal work arrived.
The famous Mine's front pipe.

This reduces the ground clearance due to the pipe size and how it hangs down so I also had to raise the ride height by around 5mm to get back into the minimum legal zone.

Underfloor braces - The braces in the rear gave me me better road feel and awareness of what the rear end and front end of the car is doing while giving a more solid, tied down feel especially when driving overimperfections in the road surfaces. 

Mine's front pipe - Due to my turbos being the BNR34 turbos so they canot make use of the extra pipe diameter of the Mine's. Furthermore the previous Fujitsubo pipe also being an equal length there wasn't a huge differnece in performance.
 There was a slight performance difference in the upper RPMs however due to the increased flow. Also the exhaust tone was abit deeper in pitch compared to the slightly higher pitch of the Fujitusbo

 This is with the Fujitsubo (HKS metal cat + Tomei Expreme Ti)

And this is with the Mine's Front pipe (HKS metal cat + Tomei Expreme Ti)