Twice Pipes were the first successful aftermarket exhaust system for the 240Z. It features a 2 1/2" inlet that splits into twin pipes measuring a little under 1 3/4" (from the head pipe back) that terminate with two glass-pack mufflers, and 2 1/2" diameter chrome tips. The kit requires no welding, and includes all parts necessary for installation. If you're looking for more power, or doing an original "performance restoration", this is the system you want. If you are not familiar with a "glass-pack" muffler, the performance "staple" of the 70's, they are very free flowing, and as such will significantly increase sound levels. Please keep this in mind when choosing the best system for your Z. Give us a call with any questions. Note: All performance exhaust systems, no matter the manufacturer or type, will be louder than the stock exhaust system. This is an unavoidable consequence of reducing back pressure and therefore increasing performance. This is especially true upon acceleration when exhaust pressures are at their highest. Twice Pipe exhaust systems, utilizing dual glass-pack mufflers, are no exception to this. While not obnoxious or "loud for the sake of being loud", this exhaust kit is noticeably louder than our kits that use a "Turbo" muffler. It will be significantly louder under heavy acceleration, especially when connected to a header as opposed to the stock exhaust manifold, but it still provides a bearable tone and volume during normal operation. Model Note: This twice-pipe system was designed for Coupes. It can be fitted to a 2+2, but would require extra piping to be purchased at an experienced muffler shop to lengthen the system enough, and installed in the proper place, for the longer 2+2 model.