XF r-sport

My XJ
So I have a 2012 XJ L portfolio, which I spent close too a thousand pounds on last week having a new engine manifold. It's done 104,000 and up until last week had never missed a beat. I now have the chance to add 3k and get a XF r-sport 2016 with 40k, it's only £30 per year to tax better on fuel and lots less miles on the clock and whilst i'm tempted it's still a downgrade. Really in 2 minds on this and over the past 4 days I've thought of nothing else. I'm still no nearer to a dissision.

What would you Do? Really need some help here.