It wont lose it's spring.
What you've done is reduced the total amount of 'twist' you can apply to the swaybar. In reality, probably not by a whole lot, but it'd be straightforward to calculate. All a bit to scientific though.
How good were your welds, they would be my main concern. Poor welds with pinholes or porosity would have me a little concerned, they could create a stress concentrator and a fatigue failure might happen. It could be a long time down the track as well.