One interesting revelation of the 2011 survey is the fact that, consistent with those results polled in 2010, the divide between Japanese car makers - traditionally in the top positions of the ranking - and other mass car makers is "becoming less and less marked, indicating that OEMs relations with suppliers are converging," said SupplierBusiness.

Top spot for 2011 goes to Porsche, overtaking both Toyota and Honda, which had been leading the ranking between 2007 and 2010. Porsche, a Stuttgart-based automaker, is the preferred customer for suppliers in Europe and Asia.

North American remains a Toyota strong hold, however both Toyota and Honda have seen their ratings drop significantly below the 650 threshold, which marks a supplier-friendly approach in the SuRe index, noted the report.  There is a more "structural change in the way the two carmakers are approaching global sourcing and in the pricing pressures that they exert on their respective supply bases in their attempts to make their cost structures more competitive," said Supplier Business. Those include the purchasing strategies enforced by both Honda and Toyota at different levels, "encompassing a more aggressive approach in their pricing policies and a wider implementation of global sourcing plans particularly in Asia and North America.

However, on the bright side "both automakers maintain a marginal advantage in the 'Organization' category which assesses how well the OEM's organization interfaces with their suppliers' personnel in a number of areas."

Suppliers rated their OEM automotive customers in five categories:  Supply (such as RFQ, sourcing information, tooling releases, and PPAP process); Profit Potential (i.e. opportunities to make money on the project); Organization  (personnel interactions); Trust (can suppliers believe what they are told, particularly in terms of pricing); Pursuit of Excellence (in terms of both technology and quality).

Volkswagen relations with its supply base are on a "downward trend" in all five categories covered by the survey. "Suppliers taking part in the study have underlined how they consider a number of its practices are becoming increasingly unfair toward them," said SupplierBusiness.  Despite that, the report noted that suppliers are "quite upbeat" about Volkswagen's outlook as a customer, "showing strong commitment towards increasing their exposure to the Wolfsburg carmaker."

Both General Motors and Ford have seen their ratings drop in 2011, joining Chrysler. Chrysler has been at the bottom of the SuRe index ranking between 2007 and 2010. The addition of Chinese automakers to the index's OEM coverage "has quite unsurprisingly put another group of carmakers at the bottom end of the ranking," noted SupplierBusiness. "While their relative position in the ranking shows these carmakers have a long way to go before establishing mutually beneficial working relations with suppliers around the globe, there are some positive sparks. For example, Changan, the highest ranked Chinese brand in the study, creeps slightly above Fiat and Seat with the exception of Chery, all Chinese carmakers are rated higher than the various GM regional purchasing entities in the "Trust" category.

The "Trust" category included questions regarding "potential retaliation, protection of intellectual property and whether the carmaker sticks with the price agreed upon when business is awarded." The reported noted that Toyota has lost ground in this area, and no longer the leader in Trust. "Suppliers surveyed in this study have complained that Toyota has become less reliable in keeping agreements on price."

However, they still rank higher than GM, which "at all levels still does not seem to have changed on some old-fashioned business practices."

Toyota and Hyundai both achieved higher SuRe index scores in North America than in other regions, while Volvo and Renault "entertain better relations with Asia-based suppliers, rather than on their home turf, Europe," said SupplierBusiness.