Don't worry if I do cut on the tank it will be the vary last thing after its all finished. Its hard to explain but even though I have always been a problem solver I have a hard time accepting alternate methods that require commitment. For example, an external over the rim hosed canister filter is a separate piece of equipment with separate potential problems that do not have to affect the main tank, You have a leak its 99% going to be the filter which you just lift and remove.
Built in pluming just cant be fix by removing the problem to the sink, tools have to be broke out, patches have to placed and maybe even the tank drained to fix the leak around the hole, basically an all nighter. With no pluming you only have to worry about the seals and then there is a 50% chance you can get away with just drain the tank 50% to fix it with a patch and a tank seal leak will most likely be a drip-drip, not a plumbing springing spray leak turn into a gusher. Also I cant stand the thought of having to have my tank at a certain water level to accommodate the overflow and the all wasted space. Since they are silicone plexiglas removal should be a razor blade away followed by two DIY bulkhead plugs and volcanic ash polish to get rid of any marks.
If the front has some deep scratched and the back is pristine, I will need that observation room without the overflows. The blue paint should come off with a little pain remover and pressure washer. If I do go saltwater it will be strictly bare bones with free desert rock, bulk commercial salt, hardware sand and my first fish will be a Grouper or two from the Chinese fish market aquarium just to get my feet wet and maybe a couple blue crabs (a rescue). Then if I have what it takes to keep them alive Ill start thinking ornamental.