Recently bought a '77 R172K that does not have a supplemental seat restraint system installed to comply with Cessna Service Bulletin SEB07-5. I have two questions:

1) What is the best system available to comply with this service bulleting -- I've seen the restractable belt style and a mechanical foot type that is mounted to the seat frame.

2) Anyone know a good source for the retractable belt system. 

I know Cessna paid for this work up until late 2009...but of course that does me no good now.

Thanks!