Asus EN8800GT 512MB - Possible 40Degree Decrease in Load TEMP :)

Hey Everyone Some of you might know, I've built a new computer, and as a GPU I have the: Asus EN8800GT 512MB... it runs around 48c on idle and around 65-70 on load.. which is not bad.. but soon i will be overclocking it once i get the cooling equipment (Will cost me £35)

Right now my GPU is:

Engine: 600Mhz
Shader: 1500Mhz
Memory: 1800Mhz

I wish to overclock it to:

Engine: 700Mhz
Shader: 1750Mhz
Memory: 2020Mhz

So it will be equivalent to the original Asus 8800GT 512mb OVERCLOCKED version.. maybe more if temperatures are kept very low

But to achieve these clock speeds.. i will be using:

Arctic Cooling Accelero S1 Rev. 2 VGA Cooler (Decreases around 30Degrees in load)

Antec Vcool (Decreases around 15 Degrees in load)

Now I'm sure they will all fit but i want to make sure they do.. because the GPU with the Arctic Cooling VGA cooler = 2 to 2and a half slots...

Antec Vcool: 2 Extra Slots (Just requires 2 PCI Slots.. this item is just a huge fan that blows cold air towards the direction of the GPU and it is in no way in contact WITH the gpu...) (Proven to decrease temp by 15degs)

I have around 5 Slots empty, that's how i can be sure it will fit, do you guys have any ideas? How cooler do you think my GPU will get?

Both of these Coolers will cost me £35 in total
And Also.. yes ive checked, my asus 8800gt is compatible with the artic cooler gpu cooler...