Which Infinity are you getting. Infinity 1 is a self install and comes with micro filter to plug in. Infinity 2 is an engineer install and if need be he/she will change the faceplate.
If you are getting Infinity 1 you use the micro filter that comes with the Homehub. Just follow the instructions that come with it.
Yes the only difference is the speed. On Infinity 1 you are capped to 38Mbps download and 10Mbps upload no matter what your line can support. On Infinity 2 you are not capped and if your line can support 78Mbps download and 20Mbps that is what you would get. Keep in mind that both are Dependant on what your line can support which is why you should get an estimate before signing up. If you don't and you purchase Infinity 2 you could be wasting your money if your line can not support speeds above 38Mbps.
RJ11 from socket to rj11 on hub. You dont need the microfilters if you already have a filtered faceplate.
I know that there are more components on the faceplate, and they go fauty when there are storms around.
I moved this thread to the Infinity board, so you may be able to get more feedback from Infinity users that have both setups, and can tell you the difference in speed.
A few have replaced the faceplate with an ordinary microfilter, due to storm damage.
If you have filters buit in you don't need to use the micro filters. They are supplied for those who do not have a filtered face plate.
If you are running a couple of meters from BT socket to hub rj11 telephone cable will suffice. I doubt you would see any drop in speed over that sort of distance.