Yes there are several back boxes suitable.
REMUS supply a back box for the GTI 6N2 with several different tail pipe options.
They dont offer a full system however. Most companies such as Magnex, Supersport, Remus, Peco, Miltek and so on have backboxes availble for the GTI but they might not be listed on their website.
Your best bet is to ring them up and tell them what your looking for, 8 times out of 10 they will have one available.
Not many companies offer a full cat-back or de-cat system for the GTI. Powerflow are one of the few that do but thats because they are custom made.
Good Luck
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