[spool twice]

It wouldn't work that way, coming from a car that had fully equal-length left/right pipes (but without a crossover), adding a crossover changed it from two 3 cylinder sounds to a true V6 sound on my Audi S5. The idea is to have all cylinder exhaust pulses in each pipe to create the sound.

You are correct with the crossover though, it doesn't do much for forced induction applications for scavenging so it's location would not matter as much as a naturally aspirated car. It impacts more of sound quality coming out the tailpipes than anything else.

Good luck to you on the pipes! I hope you don't have inspections like that German guy who has to go through inspections each year, sounds tough to get modifications done in Europe.