http://www.imsa.com/sites/default/files/uploads/2011_CTSCC_Daytona_OfficialResults.pdf
How exactly did the Imsa sanctioning of the American Le Mans series in 2011 cause the cost of the completely separate Grand-Am series to rise?
That was the start of the problem in 2011. The regs changed because GA wanted the series to get closer to GT4 specs(bad idea). I complained about that back then, and I was mocked on here for it. GA ran the Subaru team off that way. Car was too stressed and constantly breaking, so Subaru backed out of their program because that team was going through spares like crazy. Nissan finally gave it up too although that probably had more to do with the dumpster fire that was their LMP1 program.
The bigger problem with IMSA management is that now teams have to show up on Tuesday for 4 races (Daytona, Road Atlanta, COTA, and 1 more VIR I think) because they're putting the Conti practices earlier in the week. Before the merger, only Daytona was that way. GA would have the whole series through tech, practiced, and qualified in 1 day. When Conti was still 60 or so cars, it took a day and a half just to get the field through tech. That problem solved itself with no one being there anymore. The GT4 Cayman makes up half of GS and the Cayman in ST is now half that class too. The BMW GT4 car isn't even made by BMW, so I don't see how that can get mass produced and sent over here for multiple teams. The Mustang is waaaaaay too expensive for the class it's racing in. It's probably about as much as the old GAGT Mustang build was.
The Camaro Stevenson ran still isn't for sale because GM/P&M only built 4 for the teams that ran Camaros. CKS who ran the new Camaro in 2014 sold their cars to Mantella who ran them last year. Mantella looks like the only team potentially coming back with them. That Camaro turned out to be a class killer. Biggest problem right there. Teams not thinking they have a fair shot.
Pretty much the same thing happened with IMSA allowing the Cayman in ST except now the class has become more/less all Caymans(that is, those who are up front). The car with a bigger motor was legal in GS under GA, but it was a major turd. BGB tried and failed to run the Cayman about 2011 or 2012. The Boxster was what was the Porsche in ST before IMSA took over.
Another shortcoming: IMSA also failed to see that a much cheaper series exists with very similar regs as Conti GS...PWC GTS. PWC's GTS field is a lot of old Conti teams who are as Dave said
Its just cash grabbing plain and simple, they were getting another 20 odd cars coming over from another series, probably figured the grid would be to big so by lifting the costs they could make some money and deter some of the smaller teams
Entry fees got higher as did fuel and tire budgets.
More complicated rule books i.e. front ride height being measured in inches while the rear is in mm. I think that was for GTD, but that's like failing intro to engineering bad by IMSA.
I could split hairs all day long if you want.
Changing to a less doom and gloom subject, here's who I want to win
P: VisitFlorida/SDR
PC: Starworks
GTLM: Ford
GTD: Lambo or Viper