anytime your transplant it causes stress.. you can limit the stress by transplanting as much of the exsisting pot/root ball as you can without disturbing them... the new soil wont affect the plant... itll just make it happy to have more root space... you can get stuff that helps limit the amount of shock/stress the plant goes through if your worried... but if you have healthy plants i wouldnt worry to much about it.. just know that for a few days after you transplant growth will stop... but it will only be for 3-4 days at most... then everything should return to normal...