CDV delete should be one of the first mods. Plus you can do it for free if your handy.
Perhaps you might need to bleed your clutch line if it was done wrong though? I'm not sure if any of our symptoms equate correctly for what the CDV Delete is supposed to accomplish. It is supposed to make engagement of the clutch quicker and bite harder on a quick shift. Previously, the car on a 1-2 shift would not grab as hard and would literally delay engagement causing the clutch to slip. The purpose was to reduce drivetrain shock when shifting hard and fast.