Mate - I am hardly an expert on commercial machines but I have kept my eyes open and I have made some minor adjustments and repairs on my FAEMA 2 group and plumbed it in. All I can say is that it might pay to take the cover off (turned off and disconnected of course from the wall) and have a look at where the leaks are coming from. What is the history of the machine - has it been looked after properly. Has the boiler regularly been emptied and re-filled with fresh water. Was a good water filter used. Was the steam wand religiously operated after being in the milk to purge the milk and stop it going back into the boiler.
Are parts available for it - Boema is Australian made I think so probably.
Are you handy and may be prepared for repairs youself. If the machine is in poor nick with milk and other crud in the boiler you might be up for a full strip down and that seems to be a very very big job.
Mate - have a look through the threads on this site if you havnt already to get an idea. I dont know what its worth but have a look on the evil bay to see what 2 groups go for - its hard to know what condition they are in though compared to the one you have your eye on.
If in doubt, get it checked by someone you can trust who can do a quick assessment. At the very least apart from the above, see what quality the water from the hot water wand is like - look and smell in the glass. Make sure the steam wand(s) work well. Make sure the groups are working properly with all buttons...look up with a torch into the groups and make sure they look ok (you can replace shower screens usually). See whether with both groups extracting its pulling 9 bar or so (make some shots) - it may be that if the extraction guage is steady but high for example (as I found recently) the bypass valve might need cleaning which is no biggie....but if the gauge is a fair bit low and/or is jumping then you might want to steer clear because a pump will be xxxy. Pull a shot with fresh coffee and see what it tastes like and the temp is about right.
Hopefully this gives you something to go on...but hopefully others who frequent this board with way more knowledge than me might see this post and add something to help you:)