Hi there Axis.
You didn't say one thing that would help us out here.
---Are you living in shared accommodation? Is it a flat your own use that's just small?
My advice below is relevant to a spousal visa.
Re: Your Accommodation
It is my understanding that they will not require you to have any sort of extravagant home, but that your home is suitable for 2 people to live in without it being over-crowded. In other words, you must supply enough evidence to satisfy them that you have a dedicated bedroom with enough space for you and your wife to live.
So for strictly visa purposes - they are looking for satisfactory evidence that you're not living in over-crowded conditions.
But, from a personal point-of-view, if you feel that your current gaff isn't gonna cut it with regards space and comfort when your lady comes over here, then by all means upgrade - if you have the £££ to do so
Regarding the checks, I don't think they'll do much if it doesn't seem dodgy.
If you give them the least amount of work to do, they'll reward you - by doing only a little work!
I hope this helped.
James.