Each category that runs in IMSA's premier series is entered into Sunday's event. Competitors from Prototype, GT Le Mans, and GT Daytona all have their own battles to fight, and to keep up with the on-track action, we've highlighted the top storyline from each class to watch for as the 2018 season surpasses its halfway point at The Glen.

The IMSA WeatherTech Sportscar Championship will hit the track at Watkins Glen this weekend for a three-class, six-hour bout. There, it will complete the third round of the Tequila Patron North American Endurance Cup which has already included this year's Rolex 24 at Daytona as well as the 12 Hours of Sebring in March. While it may be the shortest race of the NAEC bunch, the Six Hours of The Glen doesn't lack entertainment as 42 cars are slated to attack the historic New York course with titles and bragging rights in the balance.

The July 1 race marks the return of the manufacturer-backed GTLM class, as it was absent from June's IMSA contest while teams were preparing for the 24 Hours of Le Mans. During their pilgrimage across the Atlantic, some marques basked in success while others left the French holy ground in discontent. Porsche fell into the former category as it claimed GTE-Pro class victory at la Sarthe, and as the Stuttgart brand comes back to the States this weekend, team pilot Laurens Vanthoor has all the momentum.

Backdating to May, Vanthoors and his No. 912 Porsche teammate Earl Bamber won at Mid-Ohio—the last race GTLM competed at prior to this weekend. After his triumph at the IMSA sprint event, he went on to pilot the Le Mans-winning No. 92 'Pink Pig' Porsche. Now, Vanthoors prepares for another hopeful masterclass run.

“I’m a believer that—generally in life, and especially also when you have a motorsport career—you have highs and lows,” Vanthoor said. “When you’re having a low, it’s hard. It’s difficult to get on top of that, but the only choice you have is to wait to get back on the highs.

“Once you’re on the high, I always call it, ‘You’re riding the wave.’ Everything you do somehow works out. By winning races and being on pole or whatever, you get more confidence, or you even drive better," Vanthoor continued. "I think that’s what we’re having now. We’re having a good season. We won Mid-Ohio, we won Le Mans, so we’re obviously on a high. We’re going to try and keep that lasting as long as we can, preferably until we win the championship. It would be a good ending.”

As it stands, Vanthoors and Bamber are currently second in the GTLM standings behind Ryan Briscoe and Richard Westbrook in the No. 67 Chip Ganassi Ford GT.