Why modify the exhaust system?

The standard exhaust system fitted to the GTST has a smaller bore size, (in comparrisson to after market exhausts) which restricts the gasses escaping from the engine & wastegate on the turbo. By limiting the gasses that flow through, this also limits how much b.h.p. you have.

The full system compromises down pipe (from the turbo) to the cat pipe, center section to back box (or muffler).

Not only is the exhaust itself  limiting the bhp, but unfortunately the cat (catalytic converter) also restricts quite a few horses. Some up to 40 b.h.p.

What should i go for?

Ideally a "straight through" with a bore of approx  2.5 to 3.0 inches. system from the turbo back is best suited for power higher power gains, or a cat replacement pipe which will also help adding up B.H.P gains.

There are a few options available for the Skyline R33 GTST, HKS, Blitz, Apexi among the "bigger" names, however I chose JapSpeeds cat back system, and also the turbo down pipe.

How to:

Depending on what type of system you have gone for, will depend on what needs to be done. Its quite literally a case of WD40'ing up some nuts & bolts waiting a while, getting the appropriate spanners / ratchet & sockets, un doing the nuts / bolts, and then WD40 up the rubber hangers, and slide off the mounting brackets.

Advisory : If you intend on replacing the turbo to cat down pipe yourself, get the correct bolts & nuts for replacement from anywhere you can. Japan uses a different size of thread to those in U.K. & European countries. It is best to replace these as they are old and put under a lot of heat, which may also mean that the heads and or threads of the nuts & bolts and might not survive the pressure needed to be applied for removal. - It is probably better to take the car to a garage for the job, as they (usually) have oxyacetylene ready to heat up and remove the damaged nut. This practice doesnt always apply to BOLTS as they become more likely to snap. This happened to me, and is unfortunate, but part of the mechanic's life at work. (shame, lol).

The cat pipe:

If you are replacing the cat pipe for any reason, wear mouth & nose protection to avoid any of the powder being inhaled. This "powder" is part of the honeycomb interior of the cat, which has broken down. It contains extremely toxic particals that does some "very bad shit" to you.

If you do inhale any, seek medical advice immediately, and tell them (or more likely, youl have to get someone that knew what you were doing) what happened.

I may not be held responsible for anything that may occur as a result of this guide being used, this includes personal injury and or damage to the vehicle or its running & operation.

I strongly advise taking the car to a proffessional fitter to be done.