I have an 97 audi a4 and I buy this SPF stuff to clean the engine, you put it in when you gas up, I don't know if it's ok for german cars? And I use 93 octane is that ok too? Or should I stick to the regular... Thanks for the help.

 

since no one chimed in yet.. DO NOT use 87 octane. 93 is perfect. and whatever spf is it will add atleast 10 hp... not really but i have no idea what it is

 

Yep forget the low grade stuff and use 93.
Your cleaner stuff, I would imagine its like seafoam you can use it in your fuel and oil? Unless it states only one or the other. For me I would just use seafoam and I have also used lucas products. I just think the oil additive is garbage and I would not suggest it except for seafoam. If you do put it in the oil drive it for like 100 miles and change your oil out.

 

what big name stores can you buy seafoam from.

 

You should be able to find it anywhere. It would be by the fuel system cleaner.