Hello all, new user here. I was wondering what transmission fluid to use in my 04 STi for synchro wear. I have the 5th to 4th grind at high rpm. When I’m cruising at 50-60 and want to downshift to 4th I get a grind even double clutching. I put a quart of Pennzoil Synchromesh in it with the remaining being Subaru fluid. My shifting has been smoother. The downshift grind is annoying and I’m thinking its probably shot the synchro. Any tips would be great. And also I tend to shift at low rpms around 2k-2.5k and I baby shift it. If I shift at 3k will it put more wear on my motor? I noticed that my shifts are smoother at higher rpms. I run Motul oil too. I’m tuned by TPG also. Is rev hang normal too? I put my clutch in and my rpms jump a few hundred rpms. Maybe tpg can tune it out? Sorry for the chaotic paragraph. Thanks!