But they would be facelifts, yours isn't a facelift - It does make a BIG difference unfortunatley. Also, ignore what they are advertised for. Its what they sell for thats important
I had much more interest in my car when it was at 16K than I have since dropping it down to 14.5K.
So far I have had offers of 6K, 7K & 9K from dealers for it & 12.5K from a private buyer, who only offered that much because of the high quality parts
Also, it wouldn't sell easy. Its silver, there are a million silver zeds for sale all cheaper than 15K. If someone was looking for a Z and came across your 56plate non facelift for 15K & a 54plate for £12K - which would they buy? I know exactly where my money would be going