that just silly talk, home made turbo swaps are totally doable - easy no, doable yes. I know of loads of turbo converted cars, most are home made. Can you completely destroy your engine, yes if you are silly and don't do stuff properly. My old 8v sei turbo is pushing triple standard power, has done over 40k miles in turbo form and still runs fine.
The only thing i agree with in that post is that its expensive really. But you know, i kinda see turbo conversions as the cheaper option to making a car fast, try make a car really fast with NA tuning costs an absolute shed load and also requires ecu work - thats mainly true in this instance as the fire engines are pretty strong and can take quite alot of boost on stock internals if you lower the compression ratio - the same is not true of all cars, my suzuki for example i could boost but it won't take alot before it destroys the bottom end, my friend boosted his and it spat the cylinder liner out at about 180bhp which was not much boost at all.
the ecu's on the 1242 16v fire is not mappable so you need to either get a full standalone ecu or a very good piggyback to get a turbo swap running safely, but the same is true of getting the most out of a NA tuned engine. You would spend just as much money, if not more, buying cams and associated parts, head work so it flows better etc etc.
So end of the day, yes its possible. But if you don't know exactly what your doing you need to do lots of reading.