The Tv transmissions at your location are Very Strong.
No antenna amplifier is required.
If the attic is wood construction with , no metal backed insulation , no metal roof , no solar panels.
Install a Wingard HD7694P antenna aimed at about 45 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/pointing/pointing.html.
It is true that Kansas City is currently UHF channels 14 thru 51.
However when more UHF channels are sold off to the Cell phone and Wireless Broadband Industries.
The remaining UHF Tv channels that are left will be very crowded and that means that Tv broadcasters will go to the VHF high band Tv channels 7 thru 13.
The HD7694P antenna is designed to receive Tv channels 7 thru 51.
A antenna installed in a attic will last almost for ever.
So install the HD7694P.
Installing a Tv antenna that is designed to receive more Tv channels is not a crime.
For 1 Tv connected use no splitter.
For 2 Tv's connected use a simple common 2 way splitter.
For 3 Tv's connected use a simple common 3 way splitter.
For 4 Tv's connected use a simple common 4 way splitter.