Hey Gusti,
As long as you don't take the truck off road, this is a wheelie bar that I made and works pretty good.
It's mainly just for onroad driving only (obviously). I drive this truck around mainly just in front of my house. I've done some minor jumping with it up and down curbs, through grass and it's held up well, except when I cartwheeled about 7 times at about 40mph. I have since shortened it a bit so it didnt stick out as far.
Wheelie bar 1
Wheelie bar 2
The "Insert Hyperlink" button is not working above so I just put the site address. Sorry.