OEM-Ish Equipment... What are my options?

[XanRules]

I've got 205/45r16s on the car for that exact reason.

 

[M-Sport fan]

I've got 205/45r16s on the car for that exact reason.

Then you should be just fine, right down to just before stancer 'slammed' ride heights.

 

[Dpro]

This. Always look at tire height in relation to the original height of 23.4". The 225/45R15 is only 23" in tire height so they are shorter than the OE size.

A good reference at this point is stay as close to OE tire height as you can but widen the tire as much as you can. The car needs as much grip as it possibly can get. Some approx. measurements from Tire Rack on sizes:

205/50R15 - 23.0"
225/45R15 - 23.0"
205/45R16 - 23.4"
215/45R16 - 23.6"
225/45R16 - 24.0"
205/50R16 - 23.9"
205/40R17 - 23.4"(OE SIZE)
215/40R17 - 23.9"

ah 205/45 16 is 23.26 not 23.4 its shorter than stock ride height.
Oh and your 215/40 17 is off as well its 23.77 not 23.9. I k ow this because I ran 215/40/17’s and like to look things up
As for 16’s
I also know this because I ran 205/45 16 RS Pro’s before I put on 215/45 16 RT660’s. So you can either go 7% taller and gain higher ultimate grip or go 8% shorter and get slightly better turn in at the expense of less ultimate grip because you have a narrower section with and tread patch.

Now this can vary as well as most manufactures do not absolutely adhere to sidewall stated section widths. My RS pros had a section width closer to if not wider than some 215’s . It probably measure out between a 210 and a 215 but not a 205.

Now my RT660’s are the same way they say 215 on the sidewall but have a section width that’s actually as wide as some 225’s . Both Federal and Falken are known for running wider than stated section widths.

Thats why its always wise to look for the measured section width vs stated . Ya Tire Rack lists that.
Federal has it on their website. Other tires it all depends.

 

[M-Sport fan]

^^^There is some variance within the sizes as concerns the height/overall diameter as well as the width, albeit not as radically different.

I.E.; some 205/50-16s are 23.9" tall and some are 24.1" tall, some 215/40-17s are 23.7" (like you've stated), and some ARE 23.9" tall as well.

 

[XanRules]

A brief bump as I'll probably do this at some point this calendar year. I'm thinking a bit more about the advantages of a progressive rate spring, like the Mountunes, for a daily driver, but I am once again totally overloaded with information. My impression is that progressive rate springs are preferable in some ways for a daily driver, offering a more comfortable ride in most situations and a little more leeway in suspension travel if you're going to be, oh, hauling a bunch of guitars and speakers in your trunk.

Anyone who knows what they're talking about want to chime in? I am not on a time crunch so I've got time to learn before I pull the trigger on the B6s (or B8s? aaaauuuuugggghhh!!!) and Swifts.

 

[Dave88LX]

Yeah I really wish there was something definitive on the B6 versus B8.

Probably going to buy through Whoosh so I will just run whatever they tell me to.

 

[kevinatfms]

B8 and any lowering spring(including the Swifts).

B6 and OE springs.