It makes no odds.

You need to mod the manifold or buy a different one either way.

If the flange is right you still need to add adapter to run an external gate, so wont cost much more to change the flange from T3 to T4 one or whatever.

But it says its a T3 flange, so it is and no prob, unless he a liar.

Its a big fuckoff turbo tho, unless everything else could support at least 500bhp id not bother fitting it.