That will come down to personal prefence.Si had features vx,dx,and cx had,well doors and a steering wheel.If you can live without a sunroof everything else can be added to the vx,cx,and dx.If your swapping the motor anyway I personally see no point in spending the extra money.
92 Si's came without a radio or abs. In 93 they came with radio's but abs was a option. I believe. After 93 I lost interest, but I think abs was an option up through 95. I'm still happy with my 92Si, I bought it new on Aug 28 1992, one of the last 92's made. Another difference is 92's came with black mirrors where later models had painted mirrors. Mine has A/C also.
The EX is a coupe. If you can get a Si with abs it would be worth it. ABS should be on every car. I know some people think its for wimps, but they don't know what they're talking about. ABS and AWD should be standard equipment on every car, I'll get off my soap box now.