Honestly, I wouldn't even think about it. Not unless you have seen this "kit" installed on other cars and good knowledge of it's quality.
I have seen many of these "kits" of one sort or another, sun roofs, covertible tops, removable hard tops, "T" tops and the like. 90% of them are
JUNK . If it wasn't designed by GM or Ford or what ever, it was designed by some guy with more dream than knowledge of design.
I have seen the HACKENIST (yes I made the word up

) junk designs with add on body modifications like that. On your car we are talking about STRUCTURE, not a fiberglass hood or something. We are talking STRUCTURE, your entire cars weigh is forced on that roof! I have had to replace the quarter inner structure on those cars before, the piece behind the quarter up to the roof. When you cut this piece out, you BETTER have the rocker supported and roof supported or it will cave in! That roof structure is an important part of the cars "frame" on a unibody.
Put some custom paint on the car if you want to make it different, don't cut it up. If you want a convertible, buy one.