Flex joints are mainly used for two reasons. The first is vibration. The close to 10 feet of exhaust pipe can act like a tuning fork if there is nothing installed to prevent this. The second is engine torque. When the engine revs, it rocks on its mounts. With 10 foot of solid pipe acting as leverage, it is not hard to see how extreme stress could be placed on the exhaust studs or turbo. If you have the stock downpipe you already have a flex pipe. If you have a custom unit though, there is a good chance you do not and maybe should consider this modification.

The ATR Downpipe and Catalytic Converter exhibited a fair degree of refinement in their manufacture. The bends of the Downpipe maintained a near constant diameter throughout with no signs of buckling. Though only subjected to a visual inspection the welds appeared for the most part solid though one non penetrating pinhole was quite visible. Grinding of the weld material was attempted along the inner surface of the junctions, but actual material removal was very minimal. Grinding was additionally ineffective as the grinder's efforts, while centered around the weld junction, followed an apparently random distribution within a 3/4 inch band.

While this product does not have a true performance improvement, it does do exactly what it is advertised to do. The main reason to run a catch can is to prevent oil from entering your intake as well as everything on the way including the intercooler. The advantage of a catch can breather combo over just a breather, is that hot oil does not get sprayed all over your engine. Less oil in your intake means less chance for detonation. This set up also eliminates back pressure from the head created by blow by gasses.

Long before you even consider an exhaust temperature gauge (EGT) you should have a boost gauge. If you are running several modifications and are worried about leaning out, this is a great tool. As with all gauges, you have to know what you're looking for before they can be of any help.