I don't have an S2 but I doubt that makes any difference in your question. I'll apologize in advance if I bore you with details you already know. I'm also assuming that you're using Richard (at Banks) method of actuating the shift rod. He uses a large shaft (shift selector shaft) that goes across the end cover that is slightly higher on the left (when looking toward the front of the car) side and protruded much more on the left side. A bracket is attached to this shaft and the rear link is attached to this bracket. I believe there are other methods of achieving the same goals.
The first thing you need to know is reverse is to the left and back toward the engine. Getting in that gate can require a fair amount of pressure. It might be more difficult than you're used to. When you look at the linkage, remember that when you push the lever to the left, you are moving the gear selector rod to the left but when you push the lever toward the front of the car, you are pushing the rear linkage shaft towards the rear which turns the gear selector shaft towards the rear. There needs to be a bend or an angle in the rear link. The greater that bend, the narrower your shift pattern. The "location link" (the link that goes from the top of the tranny to the rear link) should be parallel to the ground.
With the linkage disconnected at the rear, try to put it in reverse by pushing the gear selector shaft to the left and turning the shaft towards the front of the car. You may need to put a bolt in the hole of the bracket to get enough leverage and grip.
That being successful, reattach the rear link and check for binding. There should be spacers between the rod end at the end of the rear link and the bracket. This gives that rod end higher misalignment. You may need to relieve some of rod end's race to allow even greater misalignment. Another thing to look at is there should be nylon bushings at the bottom end of the gear shift lever. They look like tiny hats that fit into the hole at the botom of the lever and the shoulder bolt goes through them. If those are damaged, they should be replaced.
I've attached a couple of pictures of mine. I couldn't get a decent picture of the front of the rear link and the cross without getting under the car, but that is attached (on my car, at least) to the frame near the front left of the motor.
Let me know if that helps or if you have any other questions.