Just wanted to contribute this to the collective knowledge
There are numerous posts of the differences between gsr and non vtec versions
Just to name some
Red striped seats
Vtec vrs Dohc mouldings
Rear glass without brake light
Engine/ tranny
Gauge cluster
Rear wing w/ brake light
And now I haven’t seen the posted before but he oem intake pipe is also different
If I’m not mistaken, the 90-91 is also different than the 92-93. (In looks, no idea about the filter) I bought one from a 90 LS, that looked different than the one I found in a 92 LS.
For those that don’t know: The difference between the gsr and the others regarding the tube is the location of the hole for the hose from the valve cover. The non-gsr location is about 5 or so inches away from the throttle body. Whereas, the gsr location is about 1 inch, very close to the throttle body. The metal hardline is also different!
Yes, the vacuum lines are different for 90-91 and 92-93, so the intakes are also different.
Yes, it does have a second filter. I have never heard of it being related to the PCV system though. This secondary filter isn’t hooked up to anything specific.
All of these differences are minor and basically unimportant.
my mistake. i’d just assumed that’s what it would have been for. that or some other ported vacuum source. hmm now i almost want to find out why the change