Loving Forza 4! Thought I would just summarise my thoughts so far!
Car dynamics now seem to be even slightly better than before - well done!
Graphics look better (marginally imo!)
More car choice is good, especially with all the new models included
Less parts off track that slow you down to 1mph, very nice!
Drifting seems 100000% better than Forza 3

Massive discounts now for car modification parts (up to 100%

)once you build up affinity with the manufacturers!
Much easier to earn achievements now! Earned about 260g in about 8 hours play time, I played forza 2 for about 50 hours and got less than this!
Love the easier accessibility of the Rivals feature
Top gear track!
.... Just a few things...
Loading screens are still lonnnggg (never mind eh!)
hmmm
There were a few more negatives but i cant think of any now!
Anyway will post up some pics later when i get home! Loving it though

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