Downsides to BTX / upside down case?

[Clementi]

I was thinking of getting a new case and doing a lot of mods to it. The main one though would be flipping the entire thing outside down and putting rubber feet on the bottom and the metal that used to be on the top onto the new top. I want the hot air from my GPU blowing straight off the card (Zalaman HSF) up to a fan on the top of the case. The mobo will still be mounted the normal way. Are there any downsides to this?

I was thinking of using this case because the drive bays all seem to be the same size, it's cheap, and I like how it looks (after I remove the front door)
http://www.newegg.com/Product/Product.aspx?Item=N82E16811226003

edit: PSU would be at bottom of case

 

[wkarma]

You can find a lot of new cases that are flipped ATX. Most of the new Lian Li's are.