1. For £100 you could do an upgrade that would give you a lot more performance than a couple hundred extra MHz out of your current CPU.
2. This will only increase the performance of your GPU unless you're buying a GPU block as well which would be a waste of money.
3. You can't be serious...
I don't want to get better gpu performance, the gainward agp 7800gs+ has an excellent closed air cooler like nvidea gtxs so I was not planning on a waterblock for that anyway.
I could easily overclock my cpu to 2.4 or 2.6ghz with aircooling and to about 2.8 to 3.2ghz with watercooling (about another 1ghz to 1.4ghz above stock speed) it is still one of the most overclockable processors ever and you could say one of the main reasons for me to not upgrade is the Nvidea Soundstorm. A new processor = a new motherboard, which means I lose the quality digital output and dolby digital live encoding. I have an AV reciever for my computer to put my games in surround sound through the digital out. The only other soundcards that have DD live are the Asus Zonar soundcards which are hellishly expensive (£150!!). I don't think I could not have my games in surround, its just so much better and my reciever does not analogue passthrough.