hi fairydust, nope.. the tiles need not be removed to fix the mixer u are getting.. cos they will use back the hot/cold water pipings laid by HDB and just changing the mixer and ur shower head... yea.. there will be height restrictions if there is pipings in ur bathroom.. just measure from ur mixer up to the piping, that will be ur height limit so that when u buy ur shower set, u can tell the person.. otherwise, ur ID should also know how to measure and let u know.. on a side note, there are 2 kinds of shower set regarding height restrictions.. 1 is fixed and the other is adjustable... ours is adjustable one so we can adjust it accordingly to our height restrictions.. =)