Well, I've owned a 3rd gen 2.0 si, 4th gen si and vtec, and currently a 98 base. All were manual. To tell you the truth you cant go wrong with any prelude that you choose. You'll have fun with anyone of them. Now lemme give you my 2 cents about the 4th and 5th gen.
4th gen:
absolutly sexy front, even better with jdm one pieces
To this day interior is amazing, especially 94 and up with the EL gauges
Interior is a little small though
H23 engine wont let you down and sounds awesome, above 5200 rpm in the H22 will bring a smile to your face
In my opinion looks better than the 5th from the factory
Manual tranny is strong and bullet proof
The 6-1/2s in the rear are a downside
5th gen:
Looks awesome, looks better fixed up than the 4th gen to me
Roomier interior than 4th gen/but not as cool
Better front and rear visibility than 4th gen
All come with H22/ downside is that some come in automatic/ dont get the auto!!!
6x9s in the rear w/ acoustic feed back (pretty damn good stock radio)
The sexiest ass/ but the front is as bad as the 4th gens rear
Only 22 pounds heavier (5M base) than the 4th gen vtec.
Reminds me of the 3rd gen (which is also a sexy beast)
Truth be told you can't go wrong with either one, I guarantee you'll love a 4th gen si or vtec or a 5th gen as long as you get it in a manual. You'll feel safe in both as well. As for the corrado STAY AWAY FROM IT!!! Its more trouble than its worth, trust me.