Yeah... a spool is just great for the street rod. Fat tires, no weight and you can't drive it in the rain or wet. I been in the WV and PA mountains too many times when rain or snow was on the mountain. Spools wait it out on the incline because they have no choice. You never drove a serious road car then. Spools suck and are illegal in half the cars I used to build for street, street/strip and other classes. Being Dqued for sometime as minimal as learning to build a proper differential was never and option for myself. Setting up an open rear with a bit of creative machining to the carrier and knowing how and why it works like magic is the better option. You can put in one clutch pack only or two but they only last so long using an open diff setup. The best option is buying a heavy duty muti-spring clutch pack and removing all the springs imo. If you set up the posi correctly it will work just fine with no chatter and no drag. The thing will be smooth with the right additives. You wouldn't know it had a spool or posi when you pick up the front tires. If it goes straight with same setup as a spool my job is done. Staying on top of a posi is work like adjusting valves for the power tour and chit like that.
Do you know why guys loose parts in a diff, repeatedly, most times?