IBM x3650 Server HDD upgrade

hi,
have above type server with RAID5 (stripped data & parity) on 3 SAS 2.5″ HDD of mere ~80GB.
I went thru past posting here on RAID5 rebuild but in my case the Server on W2K3 Std Ed runs ok but has just run out of space.
Can I swap – one at a time- with 300GB drive? would the rebuild occur automatically? Intention is to replace all 3 existing drives with bigger 300GB capacity.
I’m not that worried about rebuild time as the Server can be left offline for few days.
Comments much appreciated.
thanx.