After extensive R&D, HKS' flagship exhaust system is now available with the ultimate performance, sound quality and appearance. Superior Spec R is the high end model of the HKS exhaust systems. The durable full titanium exhaust system is lightweight and weighs 10kg (22 lbs.) lighter than the stock exhaust system.

The large radius piping layout optimizes exhaust gas pressure and temperature allowing peak performance and an aggressive exhaust tone. Dual layer titanium tips reduce heat while the functional slits inside the tips assist in noise reduction.

Also features 124mm quad tips and 85mm diameter titanium piping.

Now for the even more special part! 

HKS Japan has introduced this model worldwide with rolled tips, as opposed to straight tips you see here.
HKS USA had Japan make it 10 exhausts with the straight tips, which looks much better than the rolled tips.  HKS Japan can not source more straight tips, they lost the supplier on it.  So these 10 are it!  And they are all right here only in the USA market, no where else. 
If you purchase this, you will have the most rare exhaust available, period, for the GT-R.  Resale value should be very high if you ever wanted to sell it! 
This is truly a once-in-a-lifetime opportunity for this exhaust!