Which NC do you find unfinished at the front? There has been 3 different NC fronts, as it was facelifted twice.
Mine is the third version, known as MK3.75, so it has 2 little front splitters.
I realise they may not be what you had in mind, but they are subtle, and you may be able to fit them to an earlier MK3 or MK3.5.
I would be wary of any additional fittings lower than the existing front bumper lower cover. My lowered 30mm NC1 scrapes on our drop kerb every time I reverse off the driveway into the road. I hate to think what would happen with an additional full width spoiler.
Mines the same, as in lowered 30mm and with additional splitter. Getting off the drive is interesting… our road is slightly on a hill if I drive up the hill and turn into drive it’s fine. If I reverse off down the hill same again, however if I go straight at it or the opposite way , it makes a right noise.