I got a newly purchased modified xbox but it happened to be an enigmah modchip installed. Based on the tutorials i have read it doesnt support a HDD swap. Since im to eager to have an xbox, i've never had the chance to search what are the latest innovations on it until i came into this site. Nothing i can do i already have bought it anyway i wanna upgrade it to a larger disk storage. Can my xbox still be modified with a newer modchip like xecuter pro? and remove the old one?

yes, just desolder the old one and put in the new one.