I made these for my L60 over two years ago. 35 mm primaries into 38 mm outlet. They have an o2 bung welded on but not drilled.
This also comes with a full exhaust, it is 38 mm mandrel bent and tig welded, there is also a side pipe which deletes the rear resonator, it is much louder with just two resonators… This will require one extra bracket added to the chassis, which any competent exhaust shop or anyone with a welder.
Will post at buyers cost.
Last L60 I had I made a set of extractors using the stainless steel water return pipes from an early commodore I had floating around. They ended up having the collector curving under the sump \
I don’t really know if they made any difference to the performance but it filled a need at the time with the stock headers cracking and the front factory pipe had giving up after an attack from runt beetles