Basically you need to heat the sidestrips ie use a heat gun or similar. Once removed you'll have left over glue which is easy to remove using methanol spirit or similar, all you need is a rag and some elbow grease. making sure the glues soft enough to strip off is a must or you'll remove paint to!
I also remember you need the bulb carriers with the lights too so make sure you do.
16v bumpers and GTi splitter is a great combination although done to death so it depends if you don't mind that being common! If you want you can fiddle with the 16v bumper to give it some individual flavour

I'd suggest keeping the 8v bumpers for that very reason though
You can also paint the centres as I suggested in shadow chrome and to colour-code go with a gloss black roof too.