Hi homeowner.
You will see other comments in these forums about recessed downlighters and you should read them.
If you have a "sealed" house curring holes in the ceiling could compromise this, depending on the way the house was sealed.
Cutting holes in the ceiling will compromise the 30 minute fire rating in a two storey house, right above the greatest source of fires - the kitchen: not a good idea. Install proprietary fire hoods above the lights.
Transformers were the cause of two separate fire scenes I investigated - ensure you have transformers that shut down in the even of heat build up.
You may not be able to place the lights exactly where you have them now - you'll need a hole to recess them in and odds are the existing lights are under a joist, so you'll have to move either side if this - do not cut the joist out of the way!
Consider surface mounted transformers with low voltage directional spots.
Downlighters are becoming a bit passé AFAICS and a new look might be just the ticket.
Just remember to fit lights with the latest ceramic bases as the glass bayonets can sometimes break when you'r ereplacing them.
Finally whatever light fitting you used - spend a more and go for the long life bulbs otherwise you'll be replacing them endlessly.
National Lighting Showrooms or wherever - shop around and you cand get them for a reasonable price.
HTH
ONQ.