Vehicle: EG Si Engine: D16Z6 Goal WHP: ~200hp, eventually ~280 Problem: Finding an Honda LSD for D-Series. What I found out after researching my options: 1. I can swap in a S20 Transmission from a JDM D15B. They came optional with an LSD. 2. These D15B LSDs don't hold HP very well. Anything around my Goal WHP #'s would make the LSD crap itself. Limit for these LSDs are 140hp. (From what I read on D-series.org) 3. If I want an LSD I have a few choices. Swap in a 96-00 EX Tranny and find an appropriate LSD later on such as a Quaife Unit. I can also keep my stock Tranny and upgrade to a Quaife Unit. My Options after researching this information: 1. Use Quaife in D16Z6 Tranny. 2. Install 96-00 EX Tranny and use Quaife Diff. Questions after researching this information: 1. I compared the EG Si and EK EX Tranny and found some differences which are shown respectively; 2nd gear: 1.900 vs 1.909 5th gear: .750 vs .702 What do these differences mean? I know that the when you change gearing you either stay in that gear longer or shorter. I know that the final drive effects your acceleration through the gears but at the cost of top speed. Would more value in a number given in a gearing value make the gear taller or shorter? 2. Would it be totally fine to stick with the Si Tranny if I am planning to use aftermarket gear ratio kits anyways? 3a. If I do decide to switch the the EX Tranny, will I have to use polyurethane bushings designed for the EX Tranny or will it be ok if I use a complete kit designed for the EG Si? 3b. Also I would still be using a clutch and flywheel designed for the D16Z6 correct? 4. How much of an improvement on the track would an LSD equipped Civic compare to a Non-LSD equiped Civic?