Like Njee I was close to buying an S-Works tarmac. The guys in my LBS (from whom I would have bought it) persuaded me instead to go for the top spec normal Tarmac – basically saying the S-works isn’t worth it.
After a discount and a handlebar upgrade I ended up saving a little over £3k for a weight compromise of about 150g and slightly lower grade carbon lay-up as against the S-works. Neither comprise I notice. And my tarmac rides and looks badass (2017 pro disc model – oddly list price seems to be £550 more now than it was 6 months ago). I spent the money I saved on a 2016 scott scale 900 RC on sale from Pedalon.
So, in summary, even if you can afford it think about the good stuff you could get for yourself with the saved money. Would you notice the difference? If yes or you want the bragging rights then fill your boots.
Mind you that Roubaix at Evans is quite a munter.