As a prefilter, cool idea to recycle an unused part, but to by it new, that tapered K&N filter is $60+ parts. It probably has enough filtering area to be your primary filter....., but seems like overkill as a pre-filter. IMO $20 for the UNI Pre-filter seems "more-better"...-cheaper, smaller, easier to clean.
KTM: 06 KTM950S & 10 KTM450EXC (690E sold
BMW: 08 R1200GSA & 74 BMW R90/6
MONTESSA: 82 COTA 349 "The White Wonder"