You will be doing more major reconstruction, with more potential for weakening the tunnel, then by simply cutting new holes.
More work, LOTSmore work, with a larger potential downside.
I recommend sticking with the tried and true.
I cannot explain the physics. But I learned a long time ago from an old-time carpenter, you can drill a round hole in a two-by-four (or any post or beam for that matter) without weakening it.
Same thing applies here. You drill two large holes (one each for pedal cluster and shift) and four small ones for the bolts. It does not weaken the tunnel.
If you want, you can weld plates to close up the old holes. But it is not necessary.
PMOSSBERG40907.465787037
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica Roadster
If you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)