Is the auto in the 135 the same as the in the 335?

yup..............

Just out of curiosity, does the 535i also use the same thing?

Tiptronic, is a type of discrete automatic transmission developed by Porsche, and used in its vehicles, and those of its licensees. BMW's proprietary version of this system is called Steptronic. Bmw has the steptronic transmission as an option for its cars. The feature that i admire about bmw's steptronic transmission is the sports mode and optional use of manual without a clutch. BMW has BASICALLY two manual type transmissions. One is the common manual where you have to depress a clutch, grab a shift lever, move the lever and let the clutch back up. The other type is SMG (or sequential manual gearbox).