wheel fitment and et help

[HD9POLOGTi]

ok i think ive finally found my wheels, however im unsre on the whole ET for a 6n2 gti my two options are

15x7/8 ET 20/15
16x8/9 ET 25/20

im willing to do some arch work but not too much what would it take to fit these

-tyre size
-arches rolled and flared
-et fitments
-camber shims???

i am really wanting the 9x16 on the back but after some research online im unsure about the ET fitments etc
any help much appreciated

link to the wheels

15's
http://www.ebay.co.uk/itm/15-BRAND-NEW- ... 45fc3f1f1c

16's

http://www.ebay.co.uk/itm/16-8J-9J-BRAN ... 45fc3f260f