Gearbox Oil Change

Hi, I've looking this forum for some time until now, I already been decided to buy a S2000 hood to replace my Silly wrecked hood but that was another history; but If some of you could help me, I'm Glad (I had a low speed crash with a Chevy, I almost wrecked the other car totally ​ and my car just had damaged the hood, the bumper and a little the inner bumper, The mechanic can't believe the bad quality of the other car )

 

Holky has 85K since may 2009; I'm the second owner, and buy her in january '13, and making 24K since then; Generally myself made the basic maintenance (and I Stretched the mayority of the car after the crash), Oil change, Tyres aligment, Lights, ETC

 

Well Here in Chile we have higher temps compared with europe or USA, so the standar oil is 10W40, in winter we had only minus 3°c degrees for a week at most :lol (I'm using Liqui Moly Super Leuchauff in replace on the Dealer's Mobil 1 10W40 mineral oil) and I already was buyed the oil for the next change, Total 8100 Xcess 5W40; and I want to change the gearbox oil, but I Can't find what oil to buy; just found this "info" on amazon http://www.amazon.co.uk/Febi-21829-Gearbox-Oil/dp/B006DHQQIE/ref=au_pf_sr_1?ie=UTF8&n=248877031&s=automotive&submodelId=22945 but I can't be sure if the gearbox for the BZG Engine uses this oil, or a compatible Oil.......

 

Also I don't know how many liters of oil I need