Doing Time Trials and Drift trials in Seasonals can bring you 1MCr per race (gold and with 200% bonus) which is 4MCr for all 4 venues and UCD does not get updated for TT/DT (game does not consider them a "day-pass" venues).
Also, current Seasonal A-Spec race - 1 lap on Nurburgring in #4 challenges - nets you another 1MCr with 200% bonus, so you can save that for the final run before actual purchasing.
let you're alt account run you're main account bobs ( all 5 or 6 forgot how many there are ) and have you're alt account send over the most expensinve selling car every day ....
other then that i have no idea , or just carry on with the game the car might be the holy grale to some but you don't need it to enjoy the game tho ...
Hey there is alway gift coupons I was lucky to receive one from a lvl23 a few days later the 2d showed up in the ucd now i have both the 2j and the 2d. Or you can use that bot or something that automatically runs the remote races through your computer my friend did that and he made me millions i had 20 mill 5 times because of him
amar212's spot on. Seasonal's are probably the fastest way to get some extra credits quick! Can't transfer raw credits from account to account though..
) and have you're alt account send over the most expensinve selling car every day .... 
