I am not sure about that... there is shit tons of stuff and it works a bit like in a RPG.
You get a task and depending on how well you performed, you get the chance of 3 different rewards.
For example, you can win an exhaust upgrade:
Your performance decides if you get the Gold, Silver or Bronze upgrade.
Every upgrade gets a random bonus, like better acceleration, higher top speed, better handling... stuff like this. Bronze gets you a standard bonus, Silver gets you a better bonus chance and Gold gives the chance for a very good upgrade with slightly higher performance.
Each upgrade adds to your "car level". The level determines which little tasks you can do along the way - like driving through little gates at high speed, driving around slalom poles and so on - mini games along your way.
That's part of the open-world and it's really nice integrated. Works good and is actually fun since the cars have a simulation'ish touch to their driving model. It ain't that easy to do really well in them.
Then there are "kits" for every car. Those are the basic tuning packages which the upgrades improve on. Those kits change the appearance and look of the car sometimes pretty harsh.
There are kits like Street, Racing, Drag, Offroad and so on. Street is the standard package giving you the look of a bit of a street racer with just subtle changes to the look. Racing makes the car look like a GT, Offroad sets the suspension higher, big wheels and so on...
I played a "Raid" yesterday: It means you get an offroad car and hunt down another car, trying to push it off the road. My offroad car was a freaking Porsche Carrera looking like a big-ass offroad buggy. Kinda weird... and that is the thing I am not sure about if I like or hate it.
Every car can be everything with those kits. I am not sure if it's actually a good idea to use a Porsche as Offroader or if the dedicated offroad car would work better. I am afraid they went for the silly looks and make them all perform similar with all kits...
And then there is that standard tuning for the looks. I think that's like the old NfS games, tons of stuff like hoods, wheels, roofs, bumpers. The presentation is awesome when the car gets dismantled and pieced together again on the screen, other than that it's just like NfS.
I like the handling of the cars not being full arcade, I like the cockpit view being very detailed and the apex viewing of the drivers head in that perspective is something that you need to get used to for a few minutes but then it's working really good. Probably best the apex viewing I had in a racing game so far. I like the detailed world with a ton of traffic. I like the engine sounds a lot, they sound believable, heavy. I like that you can drive according to the rules although you don't rewarded for it in any way. I like the choice of cars I've seen so far, beautifully modelled with crisps textures. I like the surrounding/environment which looks great at speed. I like that you ghost through AI cars in races cuz AI cars always suck, no matter which racing game (dunno about MP races)...
I do like a lot of things about it and yet, I am not sure if I would enjoy it.
There seems to be a lot of things to do, even as a Singleplayer, take the MP into account which is the main feature, you get a ton of content which has been fun so far.
Still... I dunno.