Forza Horizon 2 – How Useful is XP in Forza Horizon 2?

I was able to find a pretty detailed guide here, but just in case that link goes down:

EDIT: Note - these barn finds may not be in order as I found #9 first, as did Rapitor

Barn Find #1 – Lamborghini Miura P400 Location: To find this car, you need to travel to the Horizon Festival and travel to the south side of the ‘HF’ pink blimp on your mini-map. You need to travel along the dirt road with wooden barricades on the sides.

Eventually, you will come across two buildings and a garage door in the middle of these buildings. Stand in front of you to find the car.

Barn Find #2 – Ferrari 250 GT Berlinetta Lusso Location: This is a pretty hard one to find, but if I can manage it, anyone can. To get this car, you need to travel to the north side of Casteletto and travel to the smaller circle showed in the image. You will find the barn right next to some buildings near trees.

Barn Find #3 – Ford Capri RS3100 Location: You will find this car in the southeast side of Montellino. You will find a tractor parked inside a shed near the location of this garage. In addition to this, the area also contains an XP board.

Barn Find #4 – Volkswagen Type 2 De Lux Location: This is another tough one to find. To find this, you need to travel to the north side of Montellino and stick to the west side of the dirt road near the area provided in the image. The garage will be located near some buildings enclosed by small stone walls.

Barn Find #5 – Jaguar XK 120 SE Location: You need to travel to the upper side of the San Giovanni Car Meet icon on your mini-map to find this amazing car. Travel up the hill and get to the right side of the ‘P’ icon to find this rusty old car.

Barn Find #6 – Ferrari GTO Location: In order to find this car, you need to travel to the small circle in the image and turn right from the intersection. You will come across a large dirt road on your left side with another small/hidden dirt road a little ahead. You need to travel to the smaller dirt road on the left side and keep on following the path to find this car.

Barn Find #7 – Jeep WILLYS MB Location: You need to travel to the designated location and you will come across a road with a small white stone border on one side. You need to find a gap in this border and go a little right from the entrance to find this car.

Barn Find #8 – Alfa Romeo Giulia TZ2 Location: Get to the area showed in the image and turn right from the intersection. Keep on going straight and you will come across large blue truck parked outside the barn find.

Barn Find #9 – Renault Alpine A1 10 1600S Location: To get this car, you need to cross the river and get to purple fields. Do note that you need to stick to the purple side of the dirt road to find this barn.

Barn Find #10 – Maserati Tipo 61 Birdcage Location: You need to get to the location shown in the image and go through the woods to find the lone barn up the hills.

All credit to Arslan Tufail at the site listed above

Unlike Forza Motorsport 5, You still need to purchase the cars in the carpack with CR (First time is usually free). The Day 1 carpack for example are all cars already purchasable as you play through (for the same price as their boring counterparts), but they have a unique livery on them. Purchased Carpacks may be different. I haven't spent enough time in the carshow to be sure ;)

EDIT: It seems there was server issues at launch and car rewards may not have been given out.

Once the servers are stabilized, we will then get to sending out payouts for 
loyalty rewards cars, Forza Rewards payouts, etc.