I don't think the exit row seats or extra leg room seats in Y. can really be classed as upgrades, but that is just me. Virgin are certainly pushing the extra leg room seats right now, several V-Flyers have reported getting a phone call a few days before the flight offering them for sale.

Having said that, they both make for a much more comfortable trip for a relatively small extra payment - unless you get the exit row seat next to the intrusive door jamb or you are more 'generously proportioned in the rear', in which case, the narrower seats can be quite uncomfortable.

Nick