If you had to do the STC yourself: forget it!
Somebody has to do it, and e.g. the Seneca < 2000kg STC was done by one pilot by himself – the well known Charles Strasser. He never even made money out of it.
Peter wrote:
Somebody has to do it,
Sure – but as said before: For a type that is already below 2t and therefore just for “saving” some landing fees the cost is very likely much higher than what you realistically can save over time – plus the substantial reduction of utility in a 1t airplane if you loose >50kg useful load…
Malibuflyer wrote:
For practical reasons I fully agree that changing the noise certificate (no idea if you finde somebody to issue a noise certificate with a different MTOW)
I think it’s in Spain & Germany where I paid my landing fee based on MTOM from the noise certificate for a G-reg DA40, I doubt I ever got asked for it elsewhere, I have seen all sort of weights in landing invoices from 1T to 1.7T, no idea where they get those numbers as I did not hand anything…
For N-reg, I generated one myself from engine & propeller (no point saying you don’t have it as get you the 10T ticket 
)
Thanks @malibuflyer
I did once investigate such a project and my first guess had been a project cost of maybe 5000 Euro. I would only engage in this if there is a huge incentive. For example you live next to a place which only allows 1000kg MTOW planes or if your airport charges you 500 Euro per month less for the hangar if you are below 1000kg. Just for a few Euros in normal landing fees between 1 and 2 tons I do not think it makes sense. 2t is obviously another matter as the overall cost delta can be very substancial depending on where you operate.
