The 14060m as you say is the classic 40mm case and is a wonderful watch. The main difference between 2 and 4 liners is of course the price. You could hopefully get a full set 2 liner for £4.5k, but a decent 4 liner will set you back a little over £5k. My old 4 liner was listed on SC this week for £5.1k and sold quickly. It was in absolutely superb condition though.
The 4 liner was only made for a few years, so there are generally fewer of them and therefore the prices do tend to be a little higher. No different to the old 5512 v 5513 years before.
Good examples of both 14060m watches are getting harder to get hold of and sell really well when listed. Prices logically will continue to rise, so get in quick whilst you can.