I'm planning on running the Denver missions for my regular roleplaying group, after our SLA Gm had to quit due to work commitments. I'm completely new to Shadowrun 4th ed as are most of my players, although i have played 3rd.

The question is how many runners are the missions designed for, as i will have 7 players. Out of those who have genned so far I have 2 street samurai, 1 Hacker, 1 Technomancer and an Infiltration Specialist(who is mumbling abot being an international jewel thief). Will I be needing to up numbers of opponents in combat sequences and suchlike to account for such a large group or is it better to just stick with them as written while my Runners learn the system?

At Gencon and Origins tables had up to 8 players.

Balancing is an act the GM does during the mission anyways, it's nothing to do with the sheer numbers of NPCs. My experience with the Denver and NYC missions is the chosen/calculated TR got bumped up by 1 for the extra two players , just for the opposition, not for the rewards calculations, OR I had the NPCs play a lot smarter to present a tougher challenge.

A great deal depends on the actual Mission Scenario as well.