I have had 5% all around on cars before and know what you mean about parking. That is why on my P5 I put 20% on bothe front door windows and the hatch window. The rest of the windows received 5%. I would just replace those windows with 20%. It will still look good and you will be able to see.
Your car looks great with that tint, but if it's hard for you to drive/park at night then maybe you should get a slightly lighter tint, 20% should be fine.
for starters I love the look of the car with tinted windows....where I live its not really an option with the heat of summer....you NEED tinted windows....but when I had our windows done...my main concern was driving at night.....if its hard for you to park because of the tint....it is hindering your vision of what is going on around you while you are moving even more....which in my opinion you should be more concerned with.
I have to agree with fellow Torontonian 'Protege5 kid'. I prefer no tint. Not only so that they can see the yellow leather interior (and me), but also makes night driving a crap-load easier.
We are not allowed to tint the driver or passanger window in BC, but anyway, I had 5% tints before it is just way to dark at night, I now have 20% and it is much easier.
Yellow and Red P5s look with a very light tint. I personally prefer cars without tints, but there are some cars and colors that benefit/look better with tints.
I'll say remove the tints and get them up to 20% or lighter. That should make you happy.
I want to tint my windows, I think it looks better on my Yellow P5. However I have the electrochromatic mirror and I feel like it is kind of a waste of money with tint, because people's headlights will be dimmer anyway. When I do decide to tint them I think I will go for the tint that starts gold at the bottom of the window, and goes black as it goes up.
I'm, probably, the only one who doesn't like front window tint. For appearance purposes, I suggest losing the front tint. That being said, if the rear tint is affecting your safety, then perhaps you should have it removed.