BA XR8 clutch woes

[shepv8]

Gday Chris and staff,
My car is a BA1 XR8 manual. Mods are : tune, advance headers, stock cats, berklee catback system, bluepower CAI , pumpgears/tensioners. The car has 90,000kms on it. I got it with 60,000kms on it and it was standard.


So,
After about 8,000kms the gears get heavy/notchy to engage and soon after this it starts to clunk on gear changes. This continues until it is impossible to engage reverse and very difficult to get forward gears. I get the clutch fluid bled and the car is like brand new, selects gears easy as, and shifts as smooth as can be. This lasts for about 7-8,000kms when I go through the whole routine again.
I told the last guys that did the fluid change, that usually the fluid comes out black , so they put in valvoline racing fluid in an effort to stop it boiling black. This was about 1500kms ago but now I have the hard to select gears issue starting to happen again. They have no idea what to do.
Im wondering if the exhaust system I have runs closer to the clutch system and is cooking the clutch fluid quicker than a standard system?
Any ideas what could be my problem, Im in wollongong and no one here has any idea.
Regards
Shep