The Official GS300 to Lexus Part Interchange thread
 

Just wanted to make this easy to acess for all of the people who were wondering. I am going to post up a couple of things I know work, because I personally have them installed in my car! May want to make this a stickie, and I will continually update the first post with new infromation when posted.

1. SC300/400 seats DO fit in the GS300. The only difference is the SC's use 2 bolts in the rear, and the GS only uses one (you only need one bolt anyways), so yes IT DOES bolt in, with no modifications required
*** The seat electronics do plug in BUT DO NOT operate***

2. Coilovers from SC300/Supra/SC400 DO FIT on the GS300 (first gen anyways :D) I have them on my car. No modifications required.

3. Brake options (keep in mind the stock wheels WILL NOT clear these calipers): Supra brake conversion, LS400 brake conversion, and for the people who care about millimeters bigger, SC400 calipers (may clear stock wheels).

radiator
 

Will my old radiator I just took out of my 94 GS fit in my 94 SC300, which has a cracked radiator?

will supra coilovers fit on a sc300?

Yes bolt right on, we put them on my buddies na-t 93 sc300 I believe most all chassis parts from supra fit the sc chassis.

It should, follow me here...if a Supra radiator fits in a GS and an SC the same way, it should fit. So I would totaly give it a try.
Yes they will. They sit a lot lower than SC coilovers, but just keep them up and they work fine.
Most of them are interchangeable. They use the same subframe

Supra rad does fit the GS but the lower mounting brackets are different

What about 2GS seats? I've searched and searched, all I can find is anecdotal evidence but nothing concrete.

Honestly, unsure on this one. Anyone got any spares laying around they want to try :D ?

I'm going to be trying this In the next few weeks. I've got some seats sorted out just need to sort out collecting them.

Today I pulled put my carpet because it was NASTY. and my seats don't move so I had to manually crank them which sucked, I'm wondering if mk3 supra seats will work. I'm gonna go to the junk yard tomorrow to do some r&d.

1. The SC300 seats, can you elaborate about the bolts? The seat HAS to have at least 4 bolts to pass a tech inspection at the track... do you mean that the SC300 has 5 bolts (one side of the rail having 2)?

Also, I have both wiring diagrams: I'll see how the pins have to be reconfigured in order for the electronics work, that should be easy.

2. On the coilovers, I had Teins for a Supra and they were awfully short specially on the rear... and very bumpy lol If you plan on tracking your car, I could see using MKIV/Soarer coilovers paired with adjustable rear arms to adjust your camber. The fronts are just fine.

Good find, amigo!

If no one gets to try the 2GS seats then I might pick one up to experiment with. There is a 2GS in a jyard near me that I can get one out of.

1. The SC's have 6 bolts haha. On the rear, they have one that mounts to like the side of the transmission tunnel and one on the ground. The only one that works in the GS is the one on the tunnel, because there isnt a place on the ground for the GS seats. There are 4 bolts holding mine down. One at each corner.
2. The rear had to be brought up a little bit, but it wasnt too bad. It wasnt like I had to completly raise them or anything. Havent driven the car yet, so I cannot comment on the ride quality.

Adding to the list some brake options.

Ok got the MK2 seats & no way are they going in a MK1 without some major modification.

The transmission tunnel bolt is at the same angle as all the other bolts & the pattern is completely square, where the MK1 is rectangular.

The seats runners aren't interchangeable between the seats either as those are also completely different.