JRB you're still way undervaluing Sterling. Have you seen his recent performances? I would argue he is twice the player he was when he joined us, add in massive transfer inflation in the two years since, the home grown tax, the fact he is only 23. If coutinho is 135m then you have to be looking at similar for Raz, maybe 115m and I think that's conservative. However you only get those kind of fees when you don't have to sell and have tied the player to a long term contract.
You might argue that Sanchez is more of the finished article, a more clinical finisher but on the flip side he's 28, not homegrown, doesnt want to be at Arsenal and most importantly is in the last year of his contract its either xx million now or nothing. All those things being considered you would be looking at Sterling plus 50m in return for Sanchez. That would be Sanchez at 60m tops and Sterling at 110m
If their circumstances were similar you might take a straight swap, the slightly more finished article and goal scorer vs the pace, potential increased sell on value and greater longevity of Sterling.
To be honest having seen Sterling recently and considering his value as home grown, there is no way I would swap him for Sanchez.
Cash only for me, take it or leave it.