If it were me, I would measure the ride height of your car as it is now, then install the new strut inserts. Drive the car for a day and then re-measure. If the ride height changes more than 1/4" or so, make a simple adjustment to the ride height adjusters. If it doesn't change much don't worry about it. Just make sure to keep everything even. That way you can save yourself the cost of a new alignment.
LEGAL DISCLAIMER: this assumes you have a good alignment now and are knowledgeable and experienced enough to mess with suspension components. After every adjustment it is nessesary to drive the vehicle to let the suspension "settle" before re-adjusting unless you have alignment plates. I sold mine a few months ago
