Since XLTs and up have the keypad for entry, it seems like all we need is the transponder chip as far as a spare key. Has anyone tried buying and programming just this? I wouldn't mind a few extra keys for $7

4D63 Chip for Mazda for Ford / ID4D63 CARBON VIRGIN TRANSPONDER CHIP
http://www.ebay.com/itm/261857879959?item=261857879959&viewitem=&vxp=mtr