New Boiler (and relocation) in my home

Jaykhjr

Hey All, I am running my 1960's American Standard boiler one final winter before sending it out to pasture.

I am debating installing the new boiler myself, but first decision I need to make is which boiler to buy.

I am looking at a Bosch Greenstar 117k BTU high efficiency boiler.my home is single zone, 2200 sq feet with 7 radiators.
Am I choosing a good size? My ceilings are 10' thoughout the house. Outside walls are 12" brick with lath and plaster on the inside. decently thick layer of insulation in the attic.

Current boiler is 210k in 165k out, but very old and inefficient.

Right now, my boiler is on the floor of my bottom basement ( I have 2 stories of basements), There is an opening directly above the current location into the upper basement and I want to place the new boiler there (wall mount)...

IF... I buy the greenstar, mount it in location, cut the old heating pipes, water supply, and gas supply, plumb them over to the new location, and, hopefully with this forums help, install the required accessories (expansion tank, pressure reg, pump, etc... **not sure if that is a complete list**)... then pay a plumber to come in and tune it/fire it up for me... do you think I am setting myself up for failure? I am pretty handy and have done a good bit of plumbing, electrical, etc. but this will be my first foray into the HVAC world, other than replacing a fan in my old furnace and a couple thermocouplers over the years.

Any input on what I need to consider, how to right size my boiler, or different models/manufacturers you recommend would be awesome. I am just looking to learn more before i jump into this.