My 99 V70 XC has the SC816 stock radio/cassette/single CD player. I'm upgrading to a double DIN Pioneer head unit. The problem is the old unit has 2 antenna leads, one with a slightly smaller plug than the other. I assume one is for the antenna on one side of the rear hatch glass and the other comes from the passenger side in-glass antenna. If I only use one, won't my reception suffer? Is there an adapter to combine the two? Or can I cut, splice and solder the two together? I'm surprised not to see any posts on this. THANKS for the help!