I agree with some of your points actually, I also think the rx7 is better looking but that has a shit engine.
I agree the R34 is more iconic but the Supra has to be second in line.
Speed you said GTR or RS6 avant? I agree but Jesus Christ I ain't got that kind of money. They are 50kish? My Supra cost me 9k and I've probably spent 10 on it and it'll have over 600bhp soon. You can't beat that power with the reliability it gives, much more reliable and tuneable that an R34 or Rx7. Whilst only falling slightly behind in the other two category.
The supras a great all round car, you can have 700bhp, drive it reliably every day, sounds great, looks great (in my opinion) and it is iconic. Can't think of many other 'affordable' cars you can say all that about.