I think they will score similar, in the higher 80´s/lower 90´s. I just feel that both aren´t make any real strides forward at the moment, but they are both high-quality racing games. If I would pick one, I think Forza will have i slightly higher grade since it is more arcadey than GT6, but for a sim enthusiast, GT6 should score quite a lot higher than Forza. That´s my diplomatic take on it :).

No.

It was fully developed by Playground games. Turn 10 helped them with some visuals. Thats it.

Honestly.....

GT6 = 85 meta

Forza 5 = 93 ( But all reviews will say best visuals by a long way. )

Its not really fair though. Forza 5 will have way better physics, way better detail, lightng, latency etc.
GT6 is runing on 256 mb ram for CPU. and 256 mb ram for GPU. Hardly fair is it.

Forza 5 will feel alot more real thanks to technology

You are not alone :).   Forza Horizon did everything what I enjoyed in Racing games it was only to short but still a great ride :). 

Gran Turismo 6 will still have Standard cars without interiors: http://www.teamvvv.com/en/news/comments/Gran-Turismo-6-will-still-have-Standard-cars-without-interiors

With Forza 5 being on a next gen console a reviewer might start to question what could be added considering that the game is on next gen, imo I think that Forza 5 should have a weather system, day night cycle but maybe it just looks to good for anyone to question this now. As for GT6 it appears to have had a lot of work done and is a step up from GT5 and it also looks fantastic.

As for which will score higher, I think it will be close, I already predicted a score of between 90 – 93 for GT6 I think Forza 5 will score between 89-91.

More fun then Forza 3 and Forza 4 yes better then those two games no it just didn't have enough depht and replay value to trump those two its definetely better then Forza 2 in my opinion though.

Well, Forza 5 should easily score better than GT6. Forza 5: 93 and GT6: 88

But the racing physics and sound engines are more advanced on Forza series since a while now, no ?

Only the lighting is more realistic in GT series.

Really? Every car in GT5 have interior... fail again Nsanity, this articl didn't know what they are talking... and GT6 didn't have more the Premim/Stardard classification... all cars can do the samething in all modes.

Again... no more Premim and Standar cars classification in GT6