Ray, taking front arm sweep out will slow the turning reaction of the car. It basically calms the car down. I tried taking the arm sweep out of a Losi one time with using TC3 front arms and the rear Losi bar. It made the car push on a loose track but felt real nice on a high bite track.
I tried adding 1mm to the inner camber link on the front and rear of the car as well as lowered the roll centers by 1mm front and rear which resulted in a car that felt lazy and had very little side bite. I lost 3-4 tenths of a second per lap. This was on a track that I felt had quite a bit of grip. Is it possible that you removed too much grip from the car so it lost its corner grip/speed?