I emailed Arrow on the West coast and got this response about their system.
The weight difference between the silencers is just under a pound. The difference in the collector weights is around two pounds.
Thank you for your interest in Arrow exhaust. I do not stock this
system here in the US. However, I am able to order it from the factory in
Italy. ETA would be a week from Monday to me. Pricing is as follows....
71495MI (collector) : $699
71809AK (aluminum silencer) : $599
71809PK (titanium silencer) : $799"