Am I hurting performance?
 

I have a Speed by design Kit, The downpipe is 2.5 I believe. I have a 3 inch over pipe, I have a invidia front pipe which appears to be about 2 inches maybe 2 and a 1/4, and a 3 inch hks catback...That front pipe does anyone think could be hurting me performance wise? Debating on buying a 3 inch front pipe just so everythings the same size.

No doubt, When you go bigger, it will work better, just get tuned for it.

Larger will flow better but its the most advantageous to have the larger pipe up front where the gas's are hottest. The small down pipe will be your first restriction.

My turbo car has a 3" down pipe and then 2.5 the rest of the way back. Im not seeking big HP so this works fine, the SBD turbo isnt very big so a nice 2.5" setup should do just fine.