phone was running slow ( 600-900 Mhz as reported by cpu-dasherx)
ok, the screen seal was tricky to get off and the guide didn't mention the fact that if you use a new seal it will stick to the screen while you attempt to reconnect the screen cables. it was tricky to get it back together because of that. The only issue I had was one of the old battery adhesive strips broke and I had to work it out.
splurge for the isclack, its makes removing the screen simple. with the 6s you have be careful because of the screen adhesive but it was super easy to apply light pressure, enough to lift the screen slightly to the tool underneath and separate the adhesive