The IMS is an IMS.
Available either via the SA distributor. You should be able to order from most bike shops.
Might be easier and similarily priced to order online from Justgastanks.com or directly from IMS.) 19 litres.
The one on LuckyStrikers bike is an Aqualine Safari. Also available from Justgastanks and I think also directly from Aqualine in Oz. 30 odd litres.
The one on my bike is a Clarke. Also (as you might have guessed) available from Justgastanks and as well from our always helpful and friendly forum supplier Topbox. 16 litres.
Clarke and IMS will set you back an estimated R 3000 - R 3500 at current exchange rates. For the Aqualine you probably look at R5K