Geforce 8800 SLI with same but diffrent company

Hi and thanks for answering.

I have an 8800GT 512mb graphic card made by xpert view
I want to SLI it now, but I cant find the same card by the same company however I heard
nvidia cards now can be mixed and matched.

which is the best card out there that I can SLI it with mine? I play COD and FSX

or can I just SLI it with same card but made by BFG, XFX, MSI...???

I am in UK and I buy from ebay or amazon. so links and product numbers are welcome.

thanks again guys for helping you're true stars and this website wouldn't do without you.

ok it does work but my advice for who ever want to SLI with flight simulator X
dont dont dont, those youtube videos showing sli are fake
its not stable at all and it doesnt make a diffrence
it actualy works faster with just 1 card rather than 2 cards sli

only Crysis worked perfectly with SLI. also windows xp 64bit doesnt seem to work
unless you have the exact same ones I did everything "I am a super computer expert so I would try everything"

so, if you want super graphics get the gtx2 don't SLI its just not worth the time
and hassle.