why does my 1/4 time suck so bad??

Yeah.. Sounds like traction problems to me.

Sub Frame Connectors, new Control Arms and some slicks for a start.

Hmmm.....Let's see if i got this right.... You are making more power but you can't get it to the ground? Alotta people would like to have your problem! First off; do you have any weight transfer to the rear? Stiff road race springs & shocks on the front will resist weight transfer. The front swaybar will too. Bigger tires put a larger footprint on the road for more traction. You can buy a tire that is softer too. Read the tread wear rating on the sidewall. 300 or less will stick better than 300+; but will wear out quicker as well. Have you installed tubular upper & lower control arms yet? Thet will help plant the tires over the flimsy & softly bushed stock control arms. Go to the track, look for other Mustangs that hook good, & talk to the owner's about the parts & setup they have.....

.....you just might find a conection to some good leftover parts cheap from when they "upgraded" due to thier making more power....