Boilers - Steam and Hot Water Systems - New Boler..nearly decided

I will be replacing my boiler soon and have looked at combi boilers and conventional and 85%ers and 95%ers and more!!
WHEW!
I am now considering the TT Excellence as it has DWH and Mod/con...
I have 2 daughters with 1.5 baths.
Dishwasher,and clothes washer.
The cost of the excellence is appealing as it is a single unit and I would expect it to be the most efficient.
The other option was a combi boiler of mid 80% efficiancy...
I have a mono bloc layout with 1" distribution pipe feeding from Tees to 1/2 in pipe to the Radiators....the water pipes for DH and cold water are 3/4 and 1/2..longest run is about 22 feet to second floor...MAin bath and Kitchen ar about 20 feet to faucets.
I did a heat calc using the BIS and also had a HVAC contractor come out..My calc was sub 50KBTU...His number was 80K for a 95%Mod/con and 90K for a 85% boiler.
Also,I see installs on these Mod/cons use copper..My system has galv. pipe.
House has 5 radiators on first floor,and 4 on second floor.
Current Burnham heats well...Toasty warm...but 30 years old..and parts no longer available..
Assistance/guidance thoughts on Combi idea??
Or go with a tank?
Thanks
MIke S

I did a heat calc using the BIS and also had a HVAC contractor come out..My calc was sub 50KBTU...His number was 80K for a 95%Mod/con and 90K for a 85% boiler.If we're talking about a heat-loss calculation here, it should not be dependent upon the boiler efficiency. It only depends on the weather assumptions and the configuration of the house.

Why such big boilers? A 50K heat loss can use a smaller cast iron boiler if that is your decision. The mod/cons usually do not go that low. I like indirects as you get longer run times (checks efficiency's) and very low stand by losses especially if piped right meaning proper size pipes and thermal traps. See link.
http://www.comfort-calc.net/Indirect_Piping.html

Find a different contractor. What Mike said about the heat loss is correct.

The TTE is a nice package, but will spend most of its time on the bottom of the modulation range. As rbeck said, you could get a lower-firing CI or modcon plus an indirect.

The Excellence is a really nice unit. You could do a lot worse. My sole issue with it would be DHW production in the off season always stranding the heat exchanger with 2.5 gallons of very hot water. Not sure how much of an efficiency hit that would cause.

I did a HEat Calc (3 Times)using the BIS and it gave me values of 44-48KBTU...How accurate is the BIS calculator?
COntractor had the Radiator sizes and thiir number,1"Pipe dia. windows(New Andersens) glazeing area,House Sq Footage,R values...Same info as me...I also felt his Heat Calc was high..80,000BTU for a 95%..
I looked at the TT110 Excellence as I wanted to use the DHW function..I thought the Excellence set up was more efficiant than a indirect???
Is the TT60 capable of indirect DHW ??
I should also add that the living room of my home has a heating fireplace..
During the winter months we get the house heated with the Boiler and while the radiators wre heating up we start the fire in the fireplace...keep the house toasty warm once the radiators get warm..and we turn the furnace off..
I can heat the house TOASTY even when the wind is HOWLING and Temps are sub Zero!!
Current Boiler is a Burnham 120000BTU..maybe 60-70% efficiant??
I am also asking for opinions regarding Burnham units..THe Alpine 80,000 is on the high end of what I want..but it has indirect DHW??
Input is appreciated!
MIke S