The 3870 is much longer. As I said the 6670 is smaller than the mobo, if the mobo fits then the video card fits.
Yes, you are correct I now noticed that both Elite 360 & 343 are same in depth i.e 17.32 inches only slight variation in width & height. As per sapphire HD6670 the lenght of card is 6.45inches.
So, I hope that this card fits right into both the cabinets. In that case, I will choose the Elite 360 which has the benefit of keeping it either vertically or horizontally for HTPC use.
Thank you very much