steering wheel shake after lowering springs

after fitting eibach pro springs, the steering wheel shakes slightly at approx 100km/h

what could be the cause?
 
went to 2 alignment shops but they can't do it on the Clio as they don't have the manufacturer alignment specifications (not many sold here)

they advised to do it at the dealer but I don't want the dealer to realize I fitted aftermarket springs and have problems with the warranty in future

is balancing required as well? aren't the wheels already balanced from the factory? how would lowering the suspension affect the wheel balance?
 
some wheels are balanced on the car at the factory - not sure what renault do on this - but usual wobble is balance problems

may be worth jacking back up and making sure the wheels are sat flush on the wheel hubs
 
A wheel weight might have come off by accident when they were handling your wheels, sounds like wheel balancing to me.
 
yes I'll upload some in the evening, but there's almost no change from stock with Eibachs... especially on the back

should have bought the H&Rs