The information supplied above is not strictly correct. The T4 is made up of three parts, the compressor housing, the turbine housing and the wastegate housing (see the picture below, so you can see what I mean ). So if you wanted to do it on the cheap, you could remove this and weld up the waste gate hole and then make an adapter plate to suit.



If you want to do it properly, then the external Garrett turbine housing without the mounting points for the internal one on the back to directly bolt on is £250 inc delivery.

However, if you want a direct replacement one and yours is in good condition, I would do you a direct swap for FREE plus carriage. This would be a like for like high flow 0.63 a/r external housing for your two piece one . And FYI it is available in smaller and larger a/r's .