Exhaust back box replacement considerations

[bashdem]

Hi guys

My 1999 IS200 SE needs a back box replacement. The weld where the mid pipe joins the silencer has rusted and split.

I'm considering getting a 2nd hand one from a breakers but could replacing it with a 2nd hand cause any issues in regards to emissions tests during the MOT? I don't want to use a 2nd hand one if it's going to cause me issues further down the line. I'm assuming the cat is closer to the engine...possibly near the manifold but I thought I'd check.

Cheers

[andyk134]

I put a Powerflow back box on mine, looks, nicer, sounds nicer and there is a marginal difference in pick up. You have manifold and down pipe with pre cats, main cat, mid pipe with silencer, rear with back box, so 4 main parts.

[LeighT]

This exact same thing has just happened to my back box. I've ordered a standard replacement for £64 through eBay, delivery due tomorrow. I'm going to attempt swapping it myself but wanted to know if there is a gasket between the back and mid sections or is there some kind of gunk or paste I need before I get started? I will find out for sure tomorrow, but I also wondered if anyone knows what size the 2 bolts are that i'm bound to shear when removing it (along with skin off my knuckles i'm sure!).