I've 2 999s, looking to shift one of them, one 2004 monoposto conversion in red, other 2006 biposto in black, shame I'm so far from you ( I'm in West Wales).
The new Supersport is in fact 4 kg lighter than your's and if you replace the OEM exhaust with a Termi, getting rid of the cat you can save about another 8kg. The new bike beats the old SS in every respect in my opinion.