[tirod]

What compression ratio does the car have? True lead additives were outlawed and can't be purchased. Most off the shelf formulas are legal alternatives that frankly aren't cost effective for street cruising. Paying an extra $10-15 a tank for a point or two of improvement can be done easily enough by sourcing a better grade at the pump.

If the motor is more than 11:1 compression, the choice of cam and it's timing would have a lot of influence over it's actual captured pressure. Basically, is the car pinging on what can be bought now? If it isn't, there's no problem to address. If it is, some new choices may need to be made.

Running on street gas and making power aren't mutually exclusive, but it is a matter of making the right choices and living with the reality of modern fuel. I'd be far more concerned about the fuel lines being incompatible with alcohol contaminants. It's a problem that is not going away. Compression can be addressed without machine work.