Yes, wings can be removed.
A section of my edited subaru22b/tooldata.xml :
QUOTE
<Wing>
<P0 Name="Wing 0" Price="0" File="L0" MassDiff="0" WindIstabilityScale="1.0" DragScale="1.0">
<Parts P0="Winga_LOD"/>
</P0>
<P1 Name="Wing 3" Price="750" File="L0" MassDiff="0" WindIstabilityScale="0.99" DragScale="0.999" mfr="71">
<Parts P0="Wingd_LOD"/>
</P1>
<P2 Name="Wing 2" Price="1500" File="L1" MassDiff="0" WindIstabilityScale="0.95" DragScale="0.995" mfr="10">
<Parts P0="Wingc_LOD"/>
</P2>
<P3 Name="Wing 1" Price="1500" File="L1" MassDiff="0" WindIstabilityScale="0.95" DragScale="0.995" mfr="22">
<Parts P0="Wingb_LOD"/>
</P3>
<P4 Name="Wing 0" Price="0" File="L0" MassDiff="0" WindIstabilityScale="1.0" DragScale="1.0">
<Parts P0=""/>
</P4>
</Wing>
Highlighted in red is the part I have added. It's a duplicate of the stock wing, except the model to use is blank. The price has been left as zero so you automatically own it, which makes sense as it's really the omission of a part. At some point I'll try mapping out which manufacturer corresponds to which code, hopefully resulting in a nice Subaru logo for the part. A similar method should work for any car, but I haven't yet tested them.