Difference between 90-91 & 92-94

i was searching body kits yesterday and saw that some kits wer for 90-91 and the others were for the 92-94. whats the difference in the front end that makes them incompatible?

Yo Laser Rs They Fit 90-91 But Its Best That You Have A 92-94 Front End Before You Begin For Best Fit

but they have lights fro the 92+ and other parts just for them will they fit too?

yea i think u have to weld the brackets on the 1990