No where safe to stash spare or tools unless a mate brings a car and you throw it in that.
Why not leave it as is? Just race it exactly same weight to see what the improvements are? unless of course your chasing a record of some sort.
Link to my efforts here, raced with baby seats in back and prams in the boot lol
http://www.fordforums.com.au/showthread.php?t=11397565