There's roll bars you can buy for buttons which will enhance the torsional rigidity.
That's why I'm considering two of those simple under-body bars that go at the front and back of the transmission tunnel. Probably cost around £70, which I can stretch to for something that I'll be able to appreciate every day.
Another pic from today:
And something that I appreciated when I drove to the coast today with my girlfriend: I was in traffic on a main road and waiting at a junction was a Eunos V-Spec. He had his hood up, and after taking a look at my car immediately dropped it

I let him out of the junction when the traffic began moving again and I got a genuine smile and a thumbs up.
I am now driving a car which brings out cameraderie from others in similar cars. It's quite a nice feeling after over six years driving a pretty anonymous hatch. I can think of a handful of other cars that'd get the same reaction - anything fairly rare or classics, old Minis, Smarts... probably not many others.
Minor update:
I think I've decided to keep the wheels it has. Just been out to have a good look at them which changed my mind. Firstly, they do look damn good on the car. On closer inspection they're Enkei 15" rims, so I'm presuming they're of reasonable quality. I'm not sure exactly what type - I tried a bit of internet research and although they're
similar to RP-01s, they
aren't them as the RPs have a small lip and these ones don't, the spokes go all the way to the edge.
By not changing I'm basically just saving a bit of money in the meantime. At some point, the wheels could probably do with re-furbishing as the laquer is peeling and bubbling in places so up-close they look a bit grim. I might even do all that myself when I have a bit of time off over Christmas.
What it
does need are new brakes. They're stopping the car perfectly well at the moment but they're a bit scored and corroded and given that I've got a bit of money put aside and that the car is for all intents and purposes a "keeper", I might as well have them done to save me the hassle down the line. I also need new tyres, so I'm going to look into what 195/50 R15 tyres would be best, especially as we're getting towards Winter.
Finally, it's getting a full service as and when I book one. It's only had an MOT literally a month ago so there shouldn't be much amiss, but as with the brakes, I may as well start with everything in tip-top shape.
First post updated with a "to do" list.