OMR,
the 155 TAS actually increases with altitude up until around 6-7000 ft and thens tails off again. This still gives a TAS at 9-10000 equal to that at sea level!
Fuel burn stays pretty static until 6000 ft then drops off significantly: 330 kg/hr at sea level, 270 kg/hr at 10000 ft, both with about 157 kts TAS.
Vne is 175 kts up to 2000 ft, then reduces to 172 at 4000 ft and thereafter at 3 kts per 1000 ft. The IAS scal has a red line that automatically moves to reflect this.
No gear limiting speed either!