Go to wal mart and get a 77 cent beach ball, works perfectly for my LL vision. Yes, it makes a difference for front loops, it's no magic looping device, but it'll give you a little more pop than without. My skirt sinks in until it hits my legs when I go for a loop without the beach ball. Beach ball could make swimming interesting though.
Other options would be the official overthrusters from IR or the jackson inflatable thingamajig. Looks kinda silly with the huge bulge, however, large loops do not look silly.