Data extension cable query

[#1]

I am thinking of asking the engineer to set up a data extension cable about 5 - 6 metres long as my master socket is placed in conveniently in the hallway.. I had couple of queries about it...
1) Will it have any significant negative impact on net speeds by using a 6 m extension cable?
2) If I feel it has a negative effect on speed will I be able to discard the extension kit and plug in the modem directly to master socket easily?

[#2]

No. Yes.

[#3]

When i had my install , BT man moved my master socket where i needed it  data extension cable  nice tea & bikkies

[#4]

thanks guys...
i will then aim to place the router and modem in a corner of my living room.

[#5]

In my experience the engineer tends to relocate the master socket. If they do then the answer to 2 is 'no'. The extension cable shouldn't have a noticeable  impact your speeds though.

[#6]

thanks bob... i will check with engineer about my question 2 before deciding..
it seems the answers to question 1 is unanimously positive which is a good start..