Exhaust blowing + cat replacement

[jga2]

Just after some advice please!

Exhaust on my 182 is making a tinny, rattling sort of sound on cold starts and proper stinks of fuel, even more so than it did before! I have a Scorpion de-cat system and I do believe that there is a leak at the manifold - to - straight pipe/cat part. I've been thinking about replacing my straight pipe with the original cat that I got when I bought the car and now is a good time to do so as I've gotta do something about the leak anyway. My question is do you reckon ill need to replace the lambda sensors too? And if I dont need to replace them do they need to come out before putting the cat on or can they stay in place whilst the work is carried out? Any advice on this much appreciated.
Cheers

 

[JB21]

The Scorpion decats are a menace to seal properly, the mani to decat is easily enough with the OE Renault kit, but the decat to cat-back is a nightmare I found, I had to get it welded up to seal the little fecker. On cold start up pop your head under the car and you'll see condensation and fumes where the leak is, then take it from there...

 

[jga2]

The Scorpion decats are a menace to seal properly, the mani to decat is easily enough with the OE Renault kit, but the decat to cat-back is a nightmare I found, I had to get it welded up to seal the little fecker. On cold start up pop your head under the car and you'll see condensation and fumes where the leak is, then take it from there...

Sweet thanks