What air filter you going to use sharky :dunno
I'll be using a K&N filter Steve
I'm not sure what the original modification was, as posted by Badger, but I found this the other day whilst looking for an owners manual. You may already know of this posting, apologies if so.
http://www.whootis.com/index.php?page=rsvrmanuals
The info has now been made a sticky on RSVR.net for anyone interested