blastfire580 :
Any idea on the gpu i should get, I was planning to buy a nvidia 1060 or 1070 bu im not sure
If you are running a 1080p non G-Sync 60Hz monitor, then the 6GB 1060 would be more than fine (spend more for the 6GB version). Even if you had a 1080p G-sync monitor it would be a good match. The 1060 averages over 100FPS with PCars 1:
https://img.purch.com/r/600x450/aHR0cDovL21lZGlhLmJlc3RvZm1pY3JvLmNvbS81L1EvNTk2MzY2L29yaWdpbmFsL2NhcnMtMTl4MTAtZnBzLnBuZw==
^^Now granted Tom's there used a 4GHz i7 6700K which would gain maybe 5-8FPS more than your CPU. But in fact you could run 1440p with Project Cars with a 1060 with maxed out settings. I ran PCars 1 at 1440p with a single GTX 970 which is about 10% slower than the 6GB 1060 and still had FPS room to spare to V-sync cap the FPS to 60.
I'm sure Project Cars 2 will be tweaked a little in graphics improvements (hard to imagine since PCars 1 is so gorgeous) but I don't see it having a big hit on performance. I was a beta tester in PCars 1 for a year (meaning an "investor" as an early adopter) before it was released to the public and Slightly Mad Studios loves Nvidia architecture. I did not join it for PCars 2.
One thing I love about Project Cars is that it responds very well to CPU overclocking, even at 1440p where most other games do not due to graphics being more the important factor. I can't give any advice about Forza 7 because there have been no hardware tests with it yet. However, Microsoft's rather light hardware demands in the recommended column hints that it will be easy on hardware (i5 4460 CPU, GTX 670 or GTX 1050Ti GPU).