I am looking to upgrade my GT powered Coupe S. I will be buying an eBay 4 2 1 downpipe. There are a few different ones, all around £200. Is anyone better / worse than each other or are they all the same?

I will then be looking to get a custom stainless exhaust the rest of the way. I want something reasonably sporty, but not drowning and too noisy (must be getting old). What size of pipe would I be looking at to make the most of the 1.3 GT?

Cheers

Boab

Standard GT is 1.75” exhaust so next best upgrade is 2”. A lot of the 4-2-1 manifolds finish up at around 1.75” so that’ll be the biggest restriction.

Best bet is to have a custom system made, that way you can have it however you want it and they generally come with a lifetime warranty. My suggestion if you are lowering it is to lose the mid box as they tend to catch on things like speed bumps on lowered polos. To kill the drone you might need a resonator in the system or have a big rear box. My system has a 2” to a round box at the back and it’s a tad on the loud side on idle. If I remake it I’ll fit a larger oval box in the space.

 

On my Volvo 940 I built a 3” system with two of the largest boxes I could fit in and it’s not too loud and has a nice pop on deceleration.