info for gen 2 PDK parts.
The part number for the centre box is 97 111 159 32 (460.99 +vat ) which is not the same as the non PSE box however I do not think you need to change it.
I have had a 997.1 with PSE which sounded very good, a 997.2 without PSE and a 997.2 with PSE and to be honest its not the loud at all.
3: 2 x Flange gasket 997 111 113 30 4.58+vat
4: 2 x Restraining strap 997 113 119 31 32.16+vat
5: 2 x Clamping sleeve 997 111 220 30 29.33+vat
9: 1 x wiring harness 997 612 905 25 145.22+vat
10: 2 x Holder 999 507 075 40 2.57+vat
11: 1 x Holder 999 507 148 40 1.04+vat
12: 1 x Holder 999 507 902 40 0.41+vat
13: 2 x Protective tube 928 574 717 05 3.82+vat
14: 2 x Screw 900 067 362 01 0.54+vat
15: 1 x Valve holder 997 111 989 30 5.74+vat
16: 1 x Change over valve 7PP 906 270 18.67+vat
17: 2 x Y-piece 928 573 727 05 7.90+vat
18: 2 x Air hose 999 239 042 40 4.95+vat
19: 2 x Flexi-pipe 997 110 016 00 42.76+vat
Not shown;
8 x M8 Nut 900 380 005 01 0.22+vat
6 x Nut 900 910 003 03 1.28+vat
2 x Hose clamp 999 512 361 02 3.85+vat
2 x Pipe 999 181 852 40 20.20+vat
3 x Holder 999 651 401 01 0.54+vat
10 x Tie wrap 999 513 076 40 0.22+vat
3 x Holder 999 507 865 40 0.87+vat
2 x Spacer sleeve 997 111 218 30 4.18+vat
Also req;
1 x Switch Choice Approx £55 + vat