no need to remove the dash, why dont you fit the tweeter to the door card, and leave the stock tweeter in place, the replacement one will sound better being run from the crossover. to power the cross over just cut the connector off the door speaker and run a cable from that to your crossover, which if your lucky will sit behind the doorcard. The run cables from the crossover to the tweeter and woofer (everything being contained on the doorcard)