Mind you, I'm just going by the description given on www.cheaperthandirt.com , I've not converted one personally. However, I'm sure if anything else was needed, they'd be the first to try and sell it to you. Lol
However, here's where it gets a little trickier, is the conversion for carry or just for the range? If you're planning on turning it into a full time 9mm for home and carry, it might be in your best interests to go ahead and swap the extractor and ejector for 9mm ones.
If you just want 9mm for the range, I wouldn't worry about swapping them.