If you talk about the Kinetics 20" mod, it makes the folded Brompton higher and longer.

It remains one of he smallest 20" folding bike but its bigger than original, as big as a Birdy 3. This because the folded rear wheel comes against the frame tubes and bottom bracket box. If the wheel diameter is increased by let say 50mm, then the rear triangle length must be increased by about 25mm and the folded length and height are increased by about 50mm too.

So a part of the Brompton advantage is lost.