Depending on what FPR you intend to use (i.e. who maps it) you may not need an uprated pump for a K04 conversion.
Running a 4 bar FPR will place more strain on the pump which if old/worn can consequently sag under load and cause you to run lean, not ideal. Much better to stick with the 3 bar FPR in these instances.
As Phil mentioned the S3 and TT BAM variants will have twin feeds and require modification, it's easier to go with an LCR one if necessary, OR run a Bosch in-line pump which can handle much greater pressures anyway.