Will I blow up my tweeters by bi-wiring?

Yes, I knew a guy who biwired his speakers and they melted...entirely. Just kidding...and no don't worry about biwiring. You should, however, be careful that your levels aren't so high that they damage your ears or that your amp clips and fries your tweeters. Many people have damaged their ears by listening at high levels on a sustained basis. This damage cannot be reversed and generally gets worse over time.

Agree with Trelja and OH61, if your speaker cables are expensive you probably will go with internal bi-wire cable, if cables are less expensive you may want to consider double runs which is slightly better sound than internal bi-wire. Only caveat is plan ahead how to connect cables at amp end with proper terminations. I have PSB Silver-i and bi-wire with double runs of cable, Sam

This is part of the design of these speakers. There will be no problems. Paul S. Barton(PSB) is one of THE best speaker designers. He covers all his bases. He would not provide the ability to bi - wire if there was any possibility for problems. I have used PSB Goldi with Carver Lightstar amps(electronically the same as the Sunfire), and have to say it is a very good match. This amp being capable of providing the significant current to make these speakers come alive. With lesser powered amps, this speaker just doesn't give its best.

No. Bi-wiring will not present any more amp watts to your than a single wiring hookup. Bi-wiring simply separates and isolates the highpass and lowpass circuits of the crossover.