Tires, new Nitto Motivos..problems

[hsb]

Just replaced the worn out tires on my 2009z, 19 inch with Nitto Motivos and now I find that the car just doesn't feel right. First impression was that they were soft, then I noticed that in acceleration the car pulls left, deceleration goes right. Tried increasing pressure from 35 to 40 then 45 and no change....had alignment checked prior to tire change and was perfect...maybe needs changed with new tires?

I am perplexed as to what the issue is,,,,are the tires just not the right ones to have on a Z, or should I go to 50 pounds??

I hope someone has some ideas as I will need to return the tires and replace with something else in the next day or two.

thanks for your help.