The MK3 manifold n downpipe will fit, you'll just need to find a way to bridge the gap between the flange on the downpipe and your front silencer. A MK3 cat bypass pipe would probably be a good start, but I dont know what bore the MK3 pipe will end at?
As for that wire is it green/red, and I asssume thats from the ABF engine loom right?