Ok well Im gonna jump aroung time lines....

Early Sept I went to Vegas. On the way to Vegas(I left in early am) I noticed half ways though the trip that going from 6th to 5th My car would kinda grind.I thought weird since this was the first time this happened.
Fast forwarded to the end of the trip (my car was valet at the hotel). I get into my car and the shifter felt more loose and went into the gears REAL easily (didnt have the usually stiff & firm feeling). So that been said I was kinda nervous cause the female valet was riding my clutch from what i seen). So I ended up going to an industrial area and test the car. So I got on it without burning out of 1st. Now I didnt shift hard into each gear and notice that my clutch felt like it was slipping in 1st,2nd & 3rd ..I stopped after this. Also the temp out this day was like 100ish. Could this have effected the performance of an stock car that bad to lose that power?
Now fast forwarded to current date... Ive try to repeat this issue MANY times and nada BUT the going from 6th to 5th grind still remains(has not got any worse).

So my questions basically are...Is it the clutch? or 5th gear syncro? It was just the weather making the clutch slip due to the heat? or the weather does rod that much power?

My previous car was a turbo'd car so that been said it was a different game when it came to the FEELING issues lol.

Ok so this been said, my car is about to barely hit 50k. I know this is the time clutches usually go out(or soonder) but Im just wonder some personal feed back to whos gone through same excite issues.

Ive read it/reserach how it could be the 5th gear sync or clutch or even possibly the fluid (I have redline with the mixer to get to close to nissan spec's).

I'm going to change the fluid back to nissans brand (pretty soon) and just see what happens.

One last thing.. for a while(before the trip to vegas) I felt my car wouldnt pull as hard on higher rpms but yet it didnt feel like it was slipping. It felt kinda like how it was when I went from my 17s to coupes 19's.