What is the difference in the s-chassis models?

In the USA the 240SX came as the following:

- S13 chassis - 1989-1994 There was a coupe and a hatchback version. There was also a limited edition convertable version. When going for the S13, most people go for the 89-93 because the 94 was available strictly as a convertable with an auto tranny. From 1989-1990 the coupe and the fastback both came with the KA24E. That's a single cam motor that puts out 140 HP and 160 lb-ft of torque. From 1991 and up it came with the KA24DE, a dual cam motor that puts out 155 HP and 160 lb-ft of torque. The S13 was also available with HICAS which is a 4 wheel steering system. Some people like it a lot and some hate it. If you plan on drifting, you don't want HICAS.

- S14 chassis - 1995-1998 Here it was available only as a coupe but got a different body styling. There are 2 different S14's though. From 1995-1996 the S14 came with oval headlights. From 1997-1998 the headlights were changed to a slanted, or "shark eye" style. That was the only difference between the 2 S14's. The S14 came with the KA24DE.

In Japan it came as 2 different models, the 180SX and the Silvia.

- S13 chassis - 1989-1998 The 180SX is the japanese version of our 240SX fastback. They are the same except for the motor that was in it. From 1989-1990 The 180SX came with the CA18DET. From 91+ the 180SX got the ever so popular SR20DET. From 1991 to 1995 I believe the SR20DET was the "redtop" and is signified by it's red valve cover. In 94 the 180sx got the S13 Blacktop. This motor was the exact same as the S13 SR20DET Redtop except the blacktop was just newer. Remember, this is the S13 blacktop. The S14 blacktop is totally different. In 96-98 the 180SX got new taillights. The silvia was also made on the S13 chassis in japan but only until 93. The S13 silvia is identical to our S13 240SX coupe except it had a different motor and different headlights. The Silvia came in 3 models in the S13 chassis. The Jack, Queen, and King. From 89-91 the Jack and Queen both got the CA18DE. From 91-93 the Jack and Queen both got the SR20DE. From 89-91 the King got the CA18DET. From 91-93 the King got the SR20DET. The SR that came in the S13 silvia's were the redtop SR's. This SR20DET had a T25 turbo

- S14 chassis - 1994-1998 On the S14 chassis, only the silvia was made. There was no 180SX made on the S14 chassis. The S14 Silvia is identical to our S14 240SX except for the motor. The S14 Silvia is like the Jack, Queen and King on the S13 chassis. The Jack and Queen both got the SR20DE while the King got the SR20DET. This SR20DET had a T28 ball bearing turbo. VVT was introduced to the SR20DET on the S14 chassis.

- S15 chassis - 1999- We didn't get the S15 chassis in the USA. The S15 got the newest version of the SR20DET. It also has the T28 ball bearing turbo like the S14. The S15 SR20DET got bigger fuel injectors that were 480 cc/min stepped up from the 370 cc/min injectors of the S13 and S14. The S15 also got a 6 speed transmission, but is said to be weak with drifters due to the thinner gears and break around 350-400 HP. I haven't really seen this proved because the Blitz S15 has about 450 HP and is still using the stock S15 tranny. VVT was used once again.