All credit goes to my boosting partner: cno81
If you decide to boost this achievement with a friend or partner, Pause>Xbox Live>Ranked Match>Custom Match>Landmark Race>Create A Match. The landmark races are the quickest way to get wins online and the achievement. Have your partner search for your match under Landmark Races, and you will both be in the same game. The game is dead in online racing so you two will be in the same lobby for the race. Alternate the wins among both partners and before you know it, achievement unlocked for 30G.. Good luck gamers..... BTW check the leaderboards for the number of wins. Go under overall wins and it will show you the number....