Can anyone tell me what sort of miles I should be getting from £20 of optimax. Last time I put £20 worth In I did 180 miles off it car seems to run fine only mods are full decat and K+N cone filter.Not complaining but just wondered if this Is right?
When using normal unleaded I get about 130-140 miles.

 

That seems good I only get 140-150 from £35 of Optimax, on my 94 WRX