There are several OEM companys here Stateside...Subaruparts.com with link below. A bit pricey but available. 1stSubaruparts is another. Both ft. or RR stut mounts available. The more general aftermarket suppliers here like RockAuto don't carry them.
http://subaruparts.com/Subaru/
11 ] FRONT SUSPENSION / FRONT SUSPENSION / STRUTS & COMPONENTS / Strut mount
Part Number: 20320PA011
strut mount Left
MSRP Core ? Online Price
$99.95 $0.00 $83.96
Add to Cart
[ 11 ] FRONT SUSPENSION / FRONT SUSPENSION / STRUTS & COMPONENTS / Strut mount
Part Number: 20320PA011
strut mount Right
MSRP Core ? Online Price
$99.95 $0.00