Well it arrived earlier today and it fits very well
I had to remove the hard drive when I first inserted the card but I put it right back afterwards.
The only problem was the power supply.
The power supply itself wasn't that big but the cords were the size of anacondas!
What I ended up doing was bundling the extra cables and leaving them on the outside of the case so as the others mentioned I had to leave the side off anyway.
For future reference if you're going to install a new power supply in a Dell Studio Desktop GET A MODULAR ONE!!!