HELP, question about memory on P5K-E

hi,

i bought my computer 1 year ago, it works like clock never overclocked, and it has
p5k-e
intel dual core e8200
nvidia gtx280
4gb 800 mhz RAM
and some other junk

now return guarantee expired 4 days ago because it was 1 year guarantee, so now i intend to overclock it a bit...

and i want to overclock CPU, from stock 2.7GHz to somewhere on 4GHz
i already ordered :

-thermalright ultra 120 extreme
-new case: antec nine hundret two (because it has 4 stock fans, quiet fans, and because it looks mean)
-3x12cm fans (1 will go on thermalright, 1 will go on side of the case, and 1 will go inside of the case)

so in total there will be
1x20cm fan BLUE LED -this so called "big boy" i think thats with reason pushes 134CFM
6x12cm fan BLUE LED -those pushes 80CFM /each
+power supply has 1 loud fan, and gtx280 also has 1 LOUD fan

so i think heat wont be a problem at all,

the problem will be RAM

because it has 800MHz i cant overclock cpu to 4GHz

i found that info on overclocking site:
utheguru.com/overclocking-an-intel-e8200-core-2-duo-processor-2

Some Additional E8200 Overclocking Tips

1. To get very high CPU speeds like those noted above - YOU WILL NEED FAST RAM that can quite happily sit at ~ 960Mhz or above. A high quality DDR2 800Mhz stick MIGHT cut it, but I’d recommend going for a min of 1066MhZ RAM (PC8500), otherwise you’re going to find your overclock will be constrained to around 3.3Ghz.

so...i need at least 1066MHz

now what do you guys recommend?

1. overclocking 800MHz to 1066?

2. buying OCZ RAM DDR2 PC2-9200 1150MHZ, REAPER HPC HL, 2X 2GB ? which is 67€ cheapest in my country, will it be compatible? because its 1150MHz

3. buying some other ram

because on asus site i have seen that p5k-e can only take 1066mhz ram, but then when i read down a bit it says:

-Native DDR2 1066 Support
To attain top performance, ASUS engineers have successfully unleashed the true potential of DDR2 memory. While in DDR2 1066 mode, ASUS´s exclusive technology offers a choice of FSB 1333 - providing great performance for 3D graphics and other memory demanding applications.

-ASUS Super Memspeed Technology
Surpass the Limit with Easy Overclocking Automatically
To attain top performance, ASUS has managed to break through current FSB and DRAM ratio proportions by utilizing Super Memspeed Technology - the latest technology that provides even more precise overclocking options to unleash the true potential of DDR3 memory. Native DDR3 1333 maximizes system performance by eliminating the bottleneck when overclocking both the CPU and memory - providing great performance for 3D graphics and other memory demanding applications.

so what now is it only 1066MHz max? or is it 1333MHz max? im confused

now i dont want to buy wrong ram which wont be compatible with my motherboard right?

tnx for all your answers guys!!