It does add weight, But the much faster and smoother shifts benefit it ALOT more then 45kg of weight, Hell just look at the Giulia QV Ring run which is 8 seconds faster then the manual, Same with Bmw and Porshce runs compared to the manuals, A Dct can make a huge difference.
And you seem to know nothing despite saying everything, Nobody here needs to be told that tyre width helps with traction, But the fact is, If you gave the GTS 315s instead of 285s, It would not make up 2 seconds lol Your telling me, The M4 which ran a 1:39.69 in normal form, And Bmw gave it new suspension, splitter, Underbody, rear diffuser, Wing, Other aero bits, Stripped out the interior, improved tranny with new gear ratios, bigger lighter brakes, 70bhp more power 40lbft more torque, Gripper tyres 265x285, And that ran 2 seconds faster...And yet 30mm rear tyres, And 40mm front tyres alone is gonna take away more then 2 seconds compared to what Bmw did? LOLOL
And weight reduction is weight reduction, More skilled lol And nobody aid bigger tyres wouldnt benefit it, The fact is it wouldnt benefit it enought to beat the GT350, You forget, Alot of cars nowadays have there car made WITH there tyres, And can even hurt the performance, Thats a proven fact that Motortrend even did with the Z/28 vs SS 1LE.
And you can say equal terms equal tyre width but it doesnt, Thats just going one way, Give them both the same tyre size, Then add a DCT on a GT350, And even then it still wouldnt be 100% equlity