OK the important post in the thread you have linked to is this one by Lozzo
http://forums.sv650.org/showpost.php...7&postcount=18
He used to sell this stuff, and I'd be inclined to listen to what he says. At the end of the day cheap leathers are cheap leathers, I've got A* leathers but my jacket was almost twice the price of the one you're looking at and I'm also a label tart and I wanted something that matched my bike.. what I'm saying here is dont get carried away by the label on the jacket OK.
Remember dont touch Frank Thomas stuff with a bargepole ( I'm basing this on my own personal experience ) and dont think the stuff we buy off the peg from the shops bears any resemblance to what the racers wear.
Agreed on the advice about trying on before you buy, If theres a branch of J & S Accessories near you anywhere, have a look in there often they have reductions / end of line stuff and you can pick up a bargain sometiimes.
I'd also recommend you think about a seperate back protector to. Dont rely on the bit of sponge in the back of the jacket....