Hello !
Its a Weitec Suspension Kit/Ultra GT/-35mm/Springs + Shocks
Last Year I paid it 370€ + 50€ for a OMP front strutbrace
at :
http://suspensionsupplies.de
In france, Suspension kit is sell 470 € ...
I didn't change the springdisc when I put the weitec, I think it was an error. I don't know if its essential.
Springs are not very rigid but you feel all the little imperfections of the road and handling is good.
It's a good kit if you change the wheels. I put this kit before changing wheels and I felt immediatly the difference but now, with only 165/60/14 it's the day and the night.
I know that Suspension supplies sell kit Koni shocks + Weitec Springs (-35mm).
But if you want a kart... I think blistein is the right choice. But i don't know anyone with blistein...
I hope that this little description help you.
Keep Cool on the road...lol !
PS : Sorry for my bad english