...i dont want to compromise quality...
get the 120-300mm os and a 2x tc, which is suppose to still produce the goods.
look here,
http://www.talkphotography.co.uk/forums/showthread.php?t=323453&highlight=120-300mm
yes it will still work no probs.Do you know if VR / OS will still work with TC's?? I must admit I've never used one outside a shop before but these results make me want to get my hands on one!