[jaykay]

In my mind just resistive/ crunch feeling is different from a crunch sound coming in on top of it.

Do you have an experienced / trust worthy Porsche specialist near you? I would have them investigate what you are feeling?

Investigate the cost vs benefit of the second gear detent; CMS shift arrester and synchro service against the recommendations of specialists/opinions

I put in a model 2nd gear detent to stave off problems sometime ago. Feel wise it gives a longer engagement path for rear gate positions, preventing "pop out". IIRC It did not smooth out the shift action and I don't believe it would help worn synchros.

Different fluids will affect synchronization but in these boxes I don't think there is much leeway for experimentation. I have Miller in there right now and would like to find the Devac or Mobil Lube PTX 75W-80 and see how that feels.

I have only worked with six speeds and they very stiff shifting transmissions. I also found double de clutch downshifts into second can really smooth things out you can do it going up too but of course it feels and is slower. I must say that can nail this completely on my old Jeep but not on the Boxster as the wonkier high clutch engagement always throws me off....I guess I have to get in there an pull the helper spring out.