As Jon said above, it's really down to a few things:
- If you buy the internals yourself, will you fit it or will you get a someone else to fit it? If you search "vis internals tfsi" you'll see my video, it's not too bad of a job to do just a bit fiddly. You will save a lot of money by doing this
- You can buy the internals and get the internals fitted by someone else - go with a tuner like R-Tech as they do this day in day out, have a dedicated clean area etc.
- If you buy the pump as Jon said it's simply unbolting and unplugging the old one and put the new one in.
If you go for the VIS internals, message VIS Motorsport directly on Facebook, he will give you the best price directly. It'll be cheaper than their website or a reseller's website.