I have a 110k g35 sport 6 MT 2007 4 door sedan. The car is usually a long distance car on generally straight roads with very little heavy traffic/city drives. Recently, going into 2nd and 3rd gear i feel like there is a little bit of slipping. seriously EVER SO SLIGHTLY the RPM's jump up and down a little. The clutch still feels tight and does not feel loose when pushed all the way down. I am not the 1st owner so I am not sure of when, if ever, the clutch/flywheel had been replaced before. In addition to this, when my car starts there is a slight rattling sound. Sometimes when I press the clutch down fully i hear a whirring sound but no burning smoking smell. I was told that this might be because of the throwout bearing on my particular model. There doesn't seem to be any leakage of fluid from the clutch so i THINK the clutch slave is intact but the fluid could definitely use a flush.
My question is there anything i should do prior to taking it in to get inspected? I was planning on getting an EF, XTR or Valeo clutch kit off ebay and bringing it in. Should i wait for them to do a diagnosis or do i need to have the parts when they look at the car? I'm not 100% sure that the throwout bearing is the reason for the car making that rattling sound either, so i am hesitant in buying another throwout bearing too. Also, any info about which stage clutch would be best for a daily car because those stages are a little confusing. THANKS!
Any insight would be great as this is my first MT car that I have needed to replace the clutch system and i really enjoy this car too ^O^