Which is the fastest twin engine piston airplane?

The Piper Seminole, which cruises at 160mph, and the Diamond DA42, which cruises at 198mph. They're not currently making the DA42 because the engine builder is in receivership. Both of these planes are primarily used as trainers. Piper Seneca V's cruise at 196mph, and Beechcraft Barons cruise at 232mph. The Piper/Ted Smith Aerostar 702 and 700, its the fastest twin out there, CRUISING SPEEDS*

Full power

75% power

65% power

55% power (ktas / kph)

285 / 527

261 / 483

245 / 453

225 / 416