when I floor it I get clouds of brown/black smoke out the back and my rear bumper is caked in SHITE
I assume that you have the boost wound up! If you get the car on the dyno you will find that at boost levels above 9-10psi the thing starts to run so rich it does not matter. Mine was in the order of 10.5 air/fuel ratio. The black smoke is unburnt fuel. While I am not recommending that you just go ahead and just do this - I found that by disconnecting the vacuum/boost line to the 'rising rate' fuel regulator I was able to achieve better air/fuel ratios. I did this on a dyno to confirm that the car was not leaning out anywhere. Not only did the car put out 10kw more at the wheels the driveability was vastly improved. As I said make sure that you check the result on a dyno.