I bought a cheap E30 325i and use it for sprints, as I can't afford to run the rally car all the time at events. It has now ended up as my daily too.
I typically do events 2 times a month in it, from autocrosses, sprints, hillclimbs; I even did a round of the Winter Race Series at Manfield in it. Good cheaper alternative and still really good fun. It owes me a bit, but if I wrote it off it's not a biggy compared to destroying my GC8 rally car (not that I haven't already bent the GC8 a bit anyway!).
Slow/cheaper cars are better anyway, teaches you much more about pushing the limits of yourself and traction compared to a fast car. I also love beating the odd quicker car in it! I would highly recommend this path if you want to learn about how to drive faster, vs just getting to drive at higher than normal road speeds.