New beam is wider, basically a semicircle added to the front and back of the current beam. So assuming we can get people to accept the new beam (you know hard it is to get the Taipan class to accept rule changes), you'll need to modify the beam landing to fit it. Personally I'd get a beam and car from Goodall while they have them.

Old Rule:
11d. Rear Beam

i. The rear beam shall be made of extruded aluminium of square or rectangular section.

Minimum wall section:
• Sides 2mm.
• Top and bottom surface 3mm.

Maximum Minimum
• Height 60mm - 50mm
• Width 55mm - 45mm

ii. Total height of beam and the traveller track not to exceed 80mm.
Corners may be radiused to a maximum of 6mm. The track for the traveller car may be extruded on to this section. A track for the trampoline deck may be recessed into the lower surface.

Proposed New rule (based upon info from Brett G)
11d. Rear Beam

i. The rear beam shall be made of extruded aluminium.

Minimum wall section:
• 2mm.

Maximum Minimum
• Height 60mm - 50mm
• Width 70mm - 45mm

ii. Total height of beam and the traveller track not to exceed 80mm.
The track for the traveller car may be extruded on to this section. A track for the trampoline deck may be recessed into the lower surface.