According to cars.com...
"No matter what you’ve heard, premium-grade gasoline won’t do more to clean deposits from your fuel injectors or other parts of the fuel system because today’s regular gas contains the same detergent additives."
I've seen conflicting info on this subject on the Internet and elsewhere. But I expect any Top Tier gas will have the same detergent additives across all grades.

First off that Silverstone beauty looks fantastic, Gene. You may find that your trunk won't stay open after installing the spoiler. I had this issue with at least one car in the past and it seems like my S2000 was one. A lot of cars with optional factory or dealer installed spoilers include stronger trunk struts, springs or torsion rods. But I may be misremembering as far as the S2000 goes. I did add a spoiler to mine but I don't recall if it had this issue or not.

 

My 2001 S2000 has the stronger torsion rods put on by my (then) husband when he installed the spoiler. It worked. My 2005 and 2007 didn't get them. It's annoying when the trunk lid closes itself if it's not fully opened.

 

That is possible, but Shell with their V-Power really push the extra additives in their advertising, I would think they might have some legal issues if they sold something that wasn't as advertised, but stranger things have happened. I think there is a difference in additives, but perhaps the additives in regular cheaper gas are good enough and adding more additives may be over-kill or of no benefit.

I just realized we have gas stations that are not Top Tier, no wonder they always sell fuel cheaper than other brands, some auto companies recommend not using gas from suppliers that are not Top Tier.

Fuel here is kissing $1.60 per litre for regular, premium over $1.85, I don't even want to know what that is per gallon, I just know it is damn expensive and I drive a lot of miles.

 

One gallon is 3.8 liters. Yeah, you don’t want to know.

 

I put CR springs on my non-CR trunk lid (with the OEM wing) and if you are not careful it will take your head off when I press the button!

 

Amusing story about regular vs premium.
I usually drive when we're together and we had my wife's car.
It didn't feel right so I asked her "Did you put regular in this?"
She was shocked that i had caught her since she didn't usually do so. ( so she says....)
I could easily feel it was down on power but it was designed for a high octane fuel.

 

ahem, Chicane Silver This is an after-market spoiler that is considerably lighter than the OEM, so there shouldn't be a problem. The OEM spoiler on my '01 had the stronger springs installed.

 

My LS460, Z3, C2S and the S2000 get the premium grade per the manufacture. The rest of the fleet-Rav4, HiHy Hybrid and Corolla get regular. Not worry about gas price, can't take the greenback with you when you expire. When I shop for vehicle, I don't shop on MPG, it's based on reliability, fun factor and comfy.

 

I never trade in my cars. I sell them myself. I was just told I could trade in mine for $26,500.

 

I was at the grocery store yesterday and I guy walked up to me and said "I love your truck." Thanks, its a '97. He said so is mine and pointed back to a really nice white Chevy truck. We both use regular.