Both gearboxes are exactly the same from outside. All the FWD A series engine share the same bellhousings for their transmissions. All the cables will fit perfectly.
Sadly, ur 0-100 projections are a bit misguided. Assuming that u shift up near the rev cut (7500-7800rpm), u are supposed to reach 100kph before even using 3rd gear. Since the 1st n 2nd gear are the same in both C52 (SVT) and C56 (BT) transmissions, i dont think u will see up to 2sec of improvement there. The ratios will only affect ur 400m sprint time.