Hello Johan
First off you need to be a bit specific.
Lights- Are they Xenon or normal halogen? Please understand that you cannot retrofit the xenons.
Colour? What colour GTI?
And now for the bad part...
There is no point buying from the UK.

1. Exchange rate. For every pound you spend you have to pay R15. Its not viable. So even though parts in the UK look cheap. You need to mutiply them by at least R15. Then add tax, vat and shipping costs. In other words...
A bumper strut. (Just a random example)
40 pounds
R600 + VAT TAX ETC which is about 25% of what the strut is worth.
R200
So R800. Thats at a minimum no shipping. Starting to think it might be cheaper?
The postage on 4 rims weighing in at 60KG in total. Thats a bumper weight or just a few parts was R12 000. Thats just shipping. Nevermind the actual cost of the part.
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Where about are you in SA? Im in Cape Town. There are a lot of writtten off GTi's from rear end accidents with perfectly good front ends. Try the scrappers here and get them at a bargain.
If you are in Cape Town an need some help...
PM me or email me on micsta13@gmail.com
Lets see what we can find for you.
Mike