@UK318IS.
Welcome to the forum. That sounds like a good car, I would say since you had it for so long and likely have taken good care, but why is it off the road?
Overall, I would say you would be fine going with a intercooled kit. I don't know of any other kit in the market offering that apart from what we have going on.
Here is a recent build in South Africa that is being finished pictures attached below.
Meanwhile, we are also having a sale on the 6 cylinder kits.
https://youtu.be/Om69b519Qdc 
https://hydemotorworks.com/sale-v3-6...2-60mm-pulley/ All members of the 318ti community will get a members only discount, just reach out to us directly at Hyde Motor Works. 