Hey Dom, I just quit my job. So I'm interested in taking on some mod jobs, as I have some extra time on my hands again. Send me a PM with your VGA details and we can work something out.
Cap mods are more of a finesse mod to the card. They can help, but it really depends on the card in question, as to how much it actually helps. A lot of times it might just mean squeezing 25-50Mhz extra, but depending on where you are with the OC, that might be what you need to get that extra placement out of your score. With some cards it can help with power delivery to the GPU or memory, and with others, having extra caps doesn't really offer more power, but serve to smooth the power ripple or noise from the voltage being delivered to the component.