ARCurtiss

I have a 2000 GS300 i am building and a 1998 GS300 complete car for parts. I noticed that the 2000 has an exhaust manifold that is more like a standard manifold, and the 1998 has a split manifold that more resembles a header. Which is better performance and sound wise?

TrueGS300

The difference is negligible. I've had both. My 98 had the longer primary looking ones. Had to replace with any used one I could find to pass smog and ended up with the manifold looking one. No difference in any way that can be felt or heard. But in theory the longer separate primaries should be better.

ARCurtiss

Thats exactly what i was thinking but wanted a more educated opinion. Thank you. Also, im parting out the 1998 for very very low prices. No engine or tranny, but most electronics, panels, windows, airbags, regulators, actuators, etc still available. 99% have already been pulled.

ta1972

iTrader: (1)

I have a 99 gs300 and looking for the complete exhaust manifolds/catalytics, because of check engine codes. It says i only can use 98-99, but is it possible to use the 2000-up assembly with some modifications? Whats the difference between the two?
Any info would be appreciate it.

Thanks

shwalker07

On the header difference; both bolt up the same to the motor but it is just the mid pipe it connects to that is different in the years due to a slightly different length from what I have heard from others.

Another option is you can run a o2 spacer after the cat that costs around $10 to keep catalytic codes away. I run 2 on mine since I bought some IS300 headers and run a straight pipe exhaust. I do not have any engine lights or issues but the only downside to those spacers is if your emissions place does visual inspections, you will fail with those installed if they see them.

ARCurtiss

No big differences really. One looks more like a manifold and the other looks more like headers. They are interchangable. I know because i have swapped them and had no issues with them bolting up. I do have a good manifold with good cats. Its off a 2000 GS300. U looking for one for your car?