It's the group TRexx, and the song is 20th Century Boy. FYI, tunes in other Mitsubishi spots are:
The Wiseguys, or maybe Wise Guys - Start the Commotion, from their 1998 CD Antidote
Groove Armada - I See You Baby
New Radicals - Get what you give, off their album Maybe you've been brainwashed too
Spacehog - In the Meantime
Adam & The Ants - Kings of The Wild Frontier
Ozzy Osbourne - Crazy Train
> What's the name of the tune with the phrase at the end '20th century toy'
: great tune! Japanese Automobile marketing rocks!!!