Board Thread:Game Discussion/@comment-27431737-20160802020108/@comment-25956839-20160802100523

If your goal is to buy all cars then buy Ferrari's in their showcase, as they are not offered for sales.

Generally don't upgrade all cars, only the one you need to complete the series.

Renault Clio Cup is worth buying, but upgrade the Ford Focus RS with R$ to complete Hot Hatch Power Match.

See RR3 Wiki:Upgrades Strategy For 100% Completion, for the recommended (cheapest) car to upgrade with

See RR3 Wiki:List of Sales so Far in particular, for the regular sales.

See User blog:RR3 Michael P/My car garage, upgrades and progress though RR3, although it's from May '15, so getting old old now, the early series haven't changed much.

I hope this helps.