with my 2600 pound E30 318 with TMS chip i get 25-MPG dricing freeway and moutain roads. Highway i get 40mpg around 80mph.
also the M42/44(4 cylinder) is an inline 4. V4 would be a street bike.
4.5 sounds good.
as for the mileage...its not that bad. My car has 140k and it can still reliably do 1000mile trips no problem.
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