dual ram system is designed for the purpose of fuel efficiency and low down torque values like other parts of engines.. so mostly for street use not for high performance.. if you want to increase engine efficiency , the air path must be as short as possible.. and there are other numerous details..
Not necessarily. There will be an optimum length depending on where you expect the engine to make the best power, as the intake behaves like an organ pipe, and you can exploit this effect to bolster the power at some speeds.
The multiram intake is tuned to work well with the standard cams fitted to the V6, so, whilst 1.you might get a few more horsepower at peak RPM, you'll lose out when a big hole appears in the midrange.
2.Unless you've fitted hot cams (and ported the heads to allow higher flow at high RPM) I doubt there's much to be gained by messing with the intake, TBH, and a heavy car like an Omega needs its' low RPM torque intact.
1-2 agreed.. but it wont be few hp.. as you also said , if engine fully modified the gains will be high depending on the engine size and throttle+valve+cam design
Kevin, as a general rule, you can get more energy by only using more air as the fuel air ratio is fix.. this means you must get maximum air possible during the piston cycle.. so for performance engines designers keep the inlet tubes as short as possible to breathe more air.. obviously long tubular structures wont help engine to breathe at higher rpms.. (of course there are other calculations like air flow velocity, flow type etc)
however, we must accept the fact that street and race usage are different.. on a race yo try to keep the revs as high as possible so air paths must be short.. but on the street your revs are comparingly low on a daily use which in that case you will need this mentioned torque.. but some of us

can sacrifice mid-range
the only solution to that is variable rate cam-valve system which the omega dont have