You’ve seen them every day. Can’t miss that glistening look when you’re on the highway.That’s the chromed, spoke wheels of multiple designs that accentuate the look of an automobile. It has been a product of the after-market that the nation’s automakers intend to embrace even further. It’s called plus sizing. Simply, it means installing larger wheels and tires on a vehicle, intending to enhance the look and increase road holding.According to the Specialty Equipment Marketing Association (SEMA), wheels and tires account for almost 25 percent of the nearly $30 billion after-market parts industry. This adds up to $7.5 billion a year.Needless to say, this might explain Detroit’s interest to capitalize on this growing trend by offering wheel and tire packages as factory optional equipment.Consider that in 1998 you could get high-performance tires and chrome alloy wheels on a Firebird for $840. Today, on a car with similar performance potential ” the BMW M3, for instance ” double-spoke alloy wheels and performance tires cost $1,750.The advent of plus sizing has led to increased costs on the original equipment manufacturer (OEM) level. These wheel and tire packages have emerged as a profit center for automakers.For example, in 2000, the largest wheel offered in the Mazda Protege line was 15 inches. Today, the Mazda 3 (Protege’s replacement) offers 15-inch wheels standard, and 17-inch wheels as an option.Some consumer advocates say the buyer should be careful when opting for larger wheels and tires from the factory or in the after market. Though the advantages of dry-road handling are obvious, sometimes these larger wheels and tires can lead to a substantially harder ride, decreased wet- and snowy-road performance, increased tire wear and lower durability. These larger tires, of course, will cost more to replace. Some of the fancy wheels require specific tires that might be hard to find from anyone other than the dealership.***Based on the number of showroom visits, the Ford Mustang made five “category” impressions, according to Yahoo’s recent popularity poll. The Mustang topped the list for coupes, convertibles, sports cars, mid-range and economy.Other category winners were Ferrari’s F480 (2005) in luxury, Toyota Sierra in vans, Toyota Tacoma in trucks, Audi A4 in wagons, Ford Escape in SUVs and BMW’s 3 series in sedans. Watch for Johnny McDonald’s Auto Biography car column very month in the La Jolla Village News.