I just bought a Tremec 3550. I had the same questions you have. There is no difference between the tko and the 3550. The only diff is the input and output shafts everything else is the same. I called D & D performance and they told me I didn't need the tko. I have the same maybe more than you done to my car.
If you get the tko you will need a new clutch (GM type). and you have to change the yoke on your driveshaft, which comes with the tko.
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'93 LX 425rwhp/410rwtq
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