I'm looking at doing this myself at some point too so I've done a lot of research.
Removing the middle section should cost around £50, changes the sound a bit but doesn't make it too loud. DSG cracks/pops should be louder but it won't sound exactly like a
290 with the same exhaust. Removing the large resonator before the middle section will make a big change, but there will be drone when cruising on motorways.
Something that could be worth trying is removing the middle section and having a smaller custom back box made (or remove all together) as the stock one is very large, will be a lot cheaper than a full cat back and should still change the sound a lot. Haven't seen anyone do this as yet though.
Full cat backs can vary from around £400 if a custom exhaust company make it, up to over £1k for the branded exhausts.
After everything I've read and all the research I'm probably going to go for a non-res milltek cat back at some point. They are expensive but should be the best all round system for sound and no drone, and I could also get the milltek downpipe in the future.
Hope this all helps!
Aaron
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