Theoretical tension

Neither. Spend it on travel and adventures!

I suspect your opening sentence (house which is probably quite modest compared to many on this forum) gives away your frame of mind, and probable outcome.

You could have said house which is probably a mansion compared to many on this forum, indicating the opposite frame of mind.

Accept the inevitable.

+1.

In some parts of the world, 100k would buy a mansion and a new wife.

After your travels and adventures are over, there will be no S1. 

My vote is S1.

So fun spending other people's money!

Get new Porsche and young lady.

get S1 and SWMBO Leaves.

buy ticket to fly in space.

buy 1 Hundred thousand lottery tickets ( what's the odds).

do as told.

buy a nice painting.

etc.

etc.

Given your modest house, I would never spend it on a Statement, nor a 552. There are so many enjoyable things to do in this world and I don't think sitting in a sofa listening to a slightly better hifi, whilst slowly deteriorating, is the way forward. Pretty dull existence, if you have a limited budget in life and that's your main goal.  

Marriage is all about compromise. Tell her you'll make do with a 552/500 and spend the rest on a nicer house.

....Yes buy one of my paintings,  for 100£k that will pretty much guarantee it as a worthy investment in the future.

There's a saying here: "When momma's not happy nobody's happy" ..

If you ignore the request for a home upgrade how long are you prepared to put up with the fallout ?

I'd spring for a new house @ $50K over and spend the difference on new kit .. she can't fault that logic plus you get new stuff.

"When things go wrong...wrong with you...it hurts me too."

https://www.youtube.com/watch?v=WgPV9DFkQFs

SS

[ "When things go wrong...wrong with you...it hurts me too."

https://www.youtube.com/watch?v=WgPV9DFkQFs

SS ]

Maybe Sneaky, but:

I can't get no ..no no no satisfaction ...

https://www.youtube.com/watch?v=HoxRFOr_sQ0

I used to think marriage was about compromise. Over time I've come to realize that comfort is more important than injecting conflict. That, and the gradual erosion of my will to resist after 25+ years of marriage.

I'm content to sit pat in my first home and with my current gear. I'd find a way to pass the £100k on to my kids so they could have a more enjoyable life.

That's easy - you don't live in your statement, so it would be the house. Only remains factor of interest would be age. If you are getting closer to retirement such a move would be less like

y and it would be in the statement direction. While I also would have other thoughts about spending that money.

I expect a larger listening room and the chance to get some builders to tweak things like dedicated mains spur or make the floor around where the speakers and hi-fi go more solid is a far larger uprade than Statement in an existing smaller room.

And if it makes your other half happy too then it is an win-win scenario. Besides, even with a Statement, if the other half is not happy you will still have lost.