So you could go Texecom Kit 86, flog off the wireless Pirs on ebay, buy some hard wired ones and a bell box
Then you need cable and a battery 7Ah is the max the 64W would take, plus you could use the micro wireless contact for the front door and you could expand wirelessly later if you wish by buying wireless devices.
You should have a front door contact whether hard wired or wireless, don't know the rest of the layout so can't comment on what sensors you should have.
however a quick guide:-
PIR for every room down stairs and in the hallway would be the norm, with the landing omitted when set at night
Door contact on the entry door
However seen some very crazy layouts of homes, along with system design that makes the alarm effectively useless