Its never a good idea to buy a 'pizza cutter' thin wheel. Especially knowing that you're gonna have to ghetto-rig it with 30mm (minimum) spacers to make it look right. It's just a real bad, not well thought out, cheap skate idea.
Just save up for something that fits correctly in the first place.
Per this detailed FAQ sheet, SE-R wheels are inadequate for 240sx or most RWD fitment needs...
zer...t-faq