Black bhai
1) Sports edition is a marketing gimmick to showcase the base varient
2) Reasonable price depends on condition
3) Wise decision in what sense? merc is a merc and a toyota mark 2 is a toyota. obviously the c180 offers a better drive. After driving and comparing both cars i rate the c180 sports as accord cb5 1998 vs mark 2 as corolla se saloon 2001. The c class is a notch over the mark2.
4) Other options in your budget would include a bmw 3 series 2000- 2004 both shapes.
Bmw M3 1998. Thats a nasty one....
You need to know exactly what you want . Once you decide , I can refer you to people who specially deal in Merc , Jags , bimmers , lexus , you name it they have it....
Get Karachi registered cars , they are relatively cheaper....all you need to worry is about the freight... to isb...
good luck....