Sorry, don't know exactly but probably it's a bigger one.
Here are the part numbers of the engines.
S3:
06F 145 702 C = exhaust manifold and turbocharger
1K0 145 803 P = intercooler, there are two of them
8P0 253 181 = middle and end exhaust silencer
Cupra (engine code BWJ):
06F 145 701 E = exhaust manifold and turbocharger
1K0 145 803 A = intercooler
1P0 253 181 D = middle and end exhaust silencer (but this is for engine code BWA, so perhaps BWJ has something else here)