Well, thanks all for your opinions and ideas, specially to konraDarnok who made me want to open a thread like this
You are right about the pentax database on this forum but it isn't much active, I have read all that it says many times and people sometimes dont bother to write in there.
I also think creating a "star*" club instead is a better idea, obviously a club for a single lens doesnt make much sense so it would be better opening minds a bit and talking at least about 300mm prime lenses or star lenses.
A thread like "Show me your F/FA* 300mm photos" is also a good idea but as heliphoto said we got pbase for that and sometimes it gets a bit boring, I prefer people debating about lenses, talking about using it with or without tripod mount, tricks about it, look my photo doing whatever, etc.
Cheers.