If i wanted to decat my classic scoob but dont know what connections it currently has ie 2.5 or 3.5 inches then if i just made sure the decat downpipe and centre section were the same then this wouldnt matter what size is on there now right? or is it more complicated than that?

Have seen quite a few 2.5 inch decat downpipes and centre sections for sale at the mo.

 

Hi mate
2.5" is the standard size,It should be made of mild steel (properly rusty by now).
If its been modified it will properly be made of stainless steel (shiny).
If your going for massive BHP or very loud then the 3" would be your best bet.
If not 2.5" is fine.
Hope this helps.

 

if the original system (oe) is still on car then it should be 2.5", u can either replace it all with 2.5 or go for a 3" system. on mine i have a 3" ninja sports cat downpipe but it tapers down to the original 2.5,so i used 2.5 decat mid section and a 2.5 backbox.i think u can pretty much do what you want cause i believe u can buy adaptors etc for different bores,but if i were u,choose wether u want to go with 2.5 or 3" and buy to suit choice.i have a friend that has the oe cat downpipe (2.5)and then also has a 3" mid section decat pipe into 3" box.so its up to u really? his 3" mid section obviously had a 2.5 flange and tapered to 3 or it came with a 2.5 adaptor flange? not sure on that one, hope this helps a bit.

 

cheers very much guys much appreciated.