whew! that's a rare bird indeed! 5spd 190e2.6s are rare enough, and a SportLine version is even rarer.
the SportLine version had a number of performance ugrades, including 8-hole wheels, stiffer springs, shocks and sway bars, sport seats and sport steering wheel (?), and maybe some other interior upgrades. Plus the telltale "SportLine" badges on the sides of the car.
my 89 5spd 190e2.6 is quite fun to drive, though it could use more roll stiffness and steering agility. Although you can use aftermarket upgrades to fix this, the SportLine package is all benz-original, and certainly has collector's item value, plus you are assured of a balanced package.
if i were in the market for this ...