I wouldnt touch the ebay ones.
Gains would be minimal using the other 2, but still slightly better than factory.
AFIA gains are only acheived when you go custom dump/front pipe and have the wastegate pipe merging much further down the line.
I could have told you that it was chinese made. The manifolds you can steer clear from- the dumps arent as bad. If you dont want it, i'll buy it back....