That clunk you hear is probably your exhaust hitting your rear axle. I had the same issue after I lowered my car. Took it to an exhaust shop and had them readjust the whole exhaust, mufflers to headers. 30 mins and 40 bucks I was good to go.

I have the FRPP K springs on mine and it gives a 1.5" drop all around. Not too extreme.

 

I had the same issue you had with the exhaust (especially since it is 3" all the way back). That was already fixed by custom bending and welding by the muffler shop. This is not a metal on metal "clank" but more of a "clunk".

After looking at Andy's picture and examining my car, I determined that my shop has already cut the bump stops. There is some clearance while parked.

My investigation continues....

 

how much clearance do you have? Im still debating on cutting mine

and yea your car does look awesome. Try pushing down on the trunk - or getting someone to push down on the trunk while you are looking under the car (open trunk and push down on the inside) and see if you can hear the noise it makes when you hit bumps and try to hear where its coming from. at least, thats what i would try.