Below are my thoughts. I'm sure other forum members will weigh in as well... and if you haven't already downloaded the full Owners Manual online, you may want to do so to help your learning (even before picking up your car). A
PDF version of the Owners Manual can be downloaded any time, and a
hard copy can be ordered after you purchase/register your car.
1. When I buy the insight I read that you should pump the tires to max psi . Does this improve anything ? Is it bad for your tires ?
The 'higher tire pressure' discussion isn't specific to the Insight, but is a general topic across all cars for optimizing mpg. At lower tire pressure, more of the tire's surface area touches the ground (i.e. friction/heat energy losses that affect mpg). At higher tire pressure, less of the tire touches the ground which helps mpg but can hurt ride comfort, reduce traction, and increase stopping distance. Overall, Honda provides inflation guidelines (see doorjamb), but it's your option as a driver/owner to adjust as long as you stay within the max pressure limits specified by the tires.
2. Do you have to constantly press this ev button or can you just keep it in ev mode?
It depends on what you're trying to achieve. Even when the EV mode button is selected, the mode gets canceled if the high voltage battery level is low, or if you're driving too fast. The max range for EV mode on full battery is ~1-2 miles, so the car isn't designed to run in EV mode forever. It will come back on as conditions allow, without you having to 'constantly press' the EV button. HOWEVER, you don't need to exclusively be in EV mode for the car to go into electric mode. The hybrid modes (Econ, Sport, Normal) also allow for EV operation, balanced with gas engine operation. You'll see an "EV" indicator in the bottom left corner of the drivers screen when electric mode kicks in. Maximizing the time that the "EV" indicator is on is a signal that you're getting the best mpg (i.e. more electric use = less gas use = higher mpg).
3. Someone in the forum said to use sport mode which somehow regeneration the battery faster . Should you switch to sport mode maybe down a hill to charge the battery faster then at the bottom of the hill switch to Econ mode?
The different modes alter the throttle response, performance, and fuel efficiency. Each mode has its pros/cons, and different suggested application based on its operation. Sport mode increases engine performance and decreases fuel economy, but is helpful for hills, curves or mountain roads because of the way it manages energy (p463 of Owners Manual). Sport mode is also the only one that allows you to set and maintain a higher level of regeneration, because it anticipates building battery reserve for high energy use/need. Going down a hill, Sport mode isn't necessary; the left regen paddle can be used to temporarily increase regen/charge in any mode if more battery charging is desired. Switching modes isn't needed for regen management; the modes are more helpful for different overall driving/performance/conditions.
4. Is Econ and normal mode the same .
They're different. Econ mode applies more conservative climate control and accelerator pedal response, which are intended to improve fuel economy (p467 of Owners Manual). Normal mode is the 'middle point' between Econ and Sport mode settings.
5. I tried out the regen paddles on my test drive but i didn’t understand them really, maybe because I was not going downhill to feel the braking.
Regen recovers energy by using the electric motor as a generator when you release the accelerator pedal, like when going downhill (p464 of Owners Manual). The amount of regeneration and deceleration force can be managed by the paddles - left paddle increases regen level (2 clicks max), right paddle decreases regen level (2 clicks min). The initial travel of the foot brake ALSO triggers regeneration, before the friction brakes engage at <5-10 mph. An overall goal of hybrid driving is to maximize the charge of your high voltage battery, so the electric engine/battery can be used instead of the gas engine. Maximizing regeneration helps to manage high voltage battery charge as much as possible.
6. Can you put the car in neutral going down a big hill in this car or is that pointless ?
If your goal is regeneration while going downhill, neutral
does not help as it disengages the engine(s). You need the electric engine to be operating for the battery to recharge (i.e. the electric engine becomes a generator for the battery when not in use for driving). The manual recommends that the transmission NOT be put in neutral while driving because regenerative braking and acceleration performance are affected (p454 of Owners Manual). But if your goal is to disconnect the engine for emergency or other reasons, neutral would make more sense.
It's vain, I admit it. But it's fun to show off this gorgeous car! 
