Well no if my maths is correct it would be 6.1 seconds wouldn't it. Which isn't that absurd actually. Provided theres traction.
Evo tested a 172 of some sort (might be ph1?) At 6.5 iirc.
It's all pub talk and let's face it, absolutely pointless.
Time and money would be better spent getting tuition on track than losing things.
I only took rear seats out of mine as it meant a better load space for wheels to track days (it's not my daily) and I have non slidy recaros so you can't get in the back anyway
Is it lighter ? Yes. Obviously.
Has it made any difference ? Yes. It's noiser than before.
Is it faster ? Yes. Physics says so.
Have I noticed any difference in performance after swapping to lighter front seats, no rear seats, no spare and no kit ? No.