The lambda should be totally fine, it's exactly why the 3.0GTV manifolds are so sort after as it's essentially a straight swap :)
Only thing you'd have to remember is that the Spider will need a remap after :)
You are correct fella, we like to fit CF2 manifolds from the 3.0GTV.
But you have to remember it'll be much much louder and that you may have to change other bits of the exhaust due to the flanges etc :)
Hope you found him or is he now lost in that rather big house :lol:
The 75 needs a lot if love but she'll be up to the same standard as the GTA in good time :)