DiRT Showdown

I would recommend doing this with a dummy account, as it's faster than boosting. your not relying on others, and one of you won't have to hit +20 to recoup the deficit. just make sure the dummy account has Dirt registered on their tag (boot the game or quit an event) so you can send challenges to it)

Most of us have a spare silver account lying around on our console, and this can be used.

Make sure you are on each others friends list, connected to XBL.

On your main profile, load showdown tour, all star and pick the San Fran Hard Target event. pick the Robson Avenger car (the weakest).

Now start the event. The aim is to die as fast as possible. If you just idle, you die in around 30-40 seconds. On the menu, hit send challenge and send to your dummy account.

Once it says challenge sent, instead of pressing continue, Hit restart and repeat ten times.

Then, switch to your guest profile, load challenges, and you will see the ten challenges you have just been sent. load each one up, and quit straight away, losing the challenge and giving your main account +1. Repeat this ten times.

Load up your main profile, and the achievement should pop upon registering the +10 difference.

To dominate a friend, this requires you to go +10 in wins on challenge mode. Although this achievement requires a friend it can be done with a dummy account if preferred (as VIP Pass is not required here)

On completing an event in Showdown Tour, you are given the option to Challenge a friend to beat your score. A win can be achieved in two ways either by beating your friends score, or your friend failing to beat your score after three attempts.

The fastest way is to play through the Tour events and send a challenge to your partner on the results screen. Your partner can then load the challenge, and then immediately quit once it starts. The game will then ask you if you want to retry, quit again here and the game will count this as a loss for your partner, and a win for you.

Repeat ten times and you will be +10 and classed as having Dominated your friend. If you wish to return favour to your friend, you will then have to have them repeat this 20 times, as they will have to go from -10, through to 0 and then to +10 and Domination.

This method ensures that no time is wasted repeating finished events as it doesn't matter how far each player has progressed in the tour.

For this achievement, you'll need someone on your friends list who has played Dirt Showdown. It requires you getting a +10 streak against a single friend.

After every Showdown Tour event you'll notice you can send a challenge to someone on your friends list. The easiest and quickest way to do this achievement is to get your friend to keep sending you Hard Target event challenges with low time scores. These should be a complete breeze to beat. Don't worry if you run out of Hard Target events to send challenges for. You can repeat the same event over and over again sending a challenge each time.

You can view your Challenges from the Front End menu, which is also where you can view your current tally.