Bruno Spengler served as a BMW M Motorsport works driver from 2012 to 2024, playing a key role in BMW's return to the DTM series and winning the championship in 2012. Additionally, he was an ambassador for BMW M Motorsport Automotive Gaming, representing the brand in various capacities during his tenure. After the 2024 season, Spengler concluded his 13-year association with BMW at his own request to pursue new professional challenges.

As there is no specific information available regarding Bruno Spengler's views on underrated brands, I cannot provide a direct answer to that question. However, considering his extensive experience in racing and representing various manufacturers, he may have insights on brands that deserve more recognition in the motorsport community or automotive industry.