Hi Aeroman76,
If you don’t want to invest in a Schlumpf Speed Drive kit, which I understand considering its high price 
, then I would suggest you to buy the bent steer.
It helps to have a more “active” position on the bike and to put more force on the pedals. Experiments prove that there is an optimal angle (between 70° & 100°) between the upper body and the upper leg when maximum force is applied on the pedal (pedal arm at 90°). That is why race cyclists or MTB riders have a crouched position on their bike. The riding position on a Strida is like on a dutch bike: ideal for the city or for riding on flats but not for sporty ride.
The bent steer is rather cheap (less that 30 Eur) and easy to install. It will also make the steering less nervous because the steer is wider. See also this topic: [url]Crouched riding position and standard steer].