The purpose of the EGR disconnect is not to affect acceleration.

Rather, when you disconnect the EGR you are eliminating a recycling of exhaust back through the intake manifold. The Exhaust that is directed back into the engine contains SOOT. The soot builds up on the interior of the intake manifold and decreases the efficiency of the system. Eventually, this will result in too little air (dirty, soot filled air) making it through into the cyliders. Part of this soot buildup problem is that the air hose leading from the back of the intake manifold (via the banjo valve) to the Injection Pump gets packed with soot, and the Injection Pump is never signalled that the Turbo is increasing the airflow to the cylinders. No signal means no increased fuel flow means the turbo can provide boost but the car performs as if no turbo was present.

So, the EGR disconnect is a long-term preventative health measure - namely soot reduction. To maximize positive effects of the EGR disconnect, clean out the air line that runs from the back of the intake manifold. Clean out the banjo valve that connects this line to the manifold. Make sure that the overboost control unit is clear (far end of air line), and then make sure the line from overboost control to the Injection Pump is clear (see archives). This is the step that can really make a severe and immediate difference in performance.

The final step is cleaning out the inside of the intake manifold. You can probably count the number of us that have gone that far on about two fingers.