Hey everyone does the 99 GS400 have just two cats compared to three in the 2001 GS430? If thats the case, after the first Y is that just a resonator? Thanks!

 

the GS400 and GS430 - both has 2 warmup cats and 1 twc cat. the last one is not a resonator, it's a cat.

 

are you sure? if you look on sewell parts and check out the diagram from 98 to 2000 the middle part only lists for 500. Now in 2001 the part lists for like 1100.

 

GS400s have 2 cats.. right off the header. the middle and the rear 2 tubes (before the muffs) are resonators.

its a straight through resonator.

(note: i had an extra OEM exhaust (cat back) sitting in my garage for awhile and confirmed that there are 3 resonators.)

 

It's a resonator. A lot of people have it removed and replaced with a straight pipe to get a nice exhaust sound from the V8 engine.

 

For the GS400, it's a resonator. For the GS430, it's a cat.