18 psi is a lot of boost pressure for a street engine. That's just over 1.2 Bar.
The Cadillac model compared to the Giulia is actually a European design. By Opel/Vauxhall with the basics from SAAB before they went under.
Michael, a little confused by your last statement about the ATS-V being a 'euro design' and the mention of Opel/Vauxhall. The ATS platform (based on the 'new' Alpha chassis introduced first by the Caddy ATS in 2013) is a GM/Caddy in-house project. Nothing owing to any international partners. The gen3 CTS, and latest Camaro also use the alpha platform. I'll grant you that this car was a bit of a departure for GM/Caddy in that it has an IRS and weight and handling were some of the priorities for the car, certainly drives/handles more like a euro sports sedan than any thing before it from GM.
A late edit:
Getting back to the 18psi comment by Michael... doesn't the Giulia QV generate something near 30psi for its 2.9L twin turbo barn stormer...? The Caddy uses somewhat small MHI turbos (in order to spool up quickly). Some aftermarket tunes have those small turbos spooling up to 21-22psi, which maxes them out. At least one aftermarket parts supplier is looking at bigger turbo kits (along with upgraded fuel delivery) but that is BIG $$$. My needs (skills) will never warrant that, but there are plenty of 'good old boys' wanting that for drag racing. Funny (frustrating actually), the social media feeds I follow, I'd say 65-70% of the performance threads deal with drag racing, roll ons, street cred, and all manner of straight line shenanigans. Heavy sigh....
The ATS-V is SO much more than that, and was actually built for tackling the track and challenging back roads. The corporate press launch of the ATS-V was held at the Circuit of the Americas F1 track in Austin, TX. Caddy was serious about the ATS-V track capabilities, and let motor journalists lap the track with a fleet of ATS-Vs! Pretty ballsy to launch a performance car at such a technically sophisticated track! This was a highly capable sports sedan meant to lure Euro luxury sports-sedan owners to Caddy, but few have ever changed marque alliances. Sad. GM's reputation preceded them, as usual. The ATS-V, such a great car, but such a marketing/sales failure!!
The ATS was introduced in 2012 as a 2013 model. The ATS-V came on to the scene as a 2016 model (late 2015). ATS-V sedan production ended in 2018, with the ATS-V coupe finally ending production in late Spring/early Summer of this year. Total production numbers for the ATS-V variant are approximately 4500 cars (about 60-65% sedans), with about a 15% take rate on the manual transmission (6sp Tremec 6060) across both V variants. I have one of the manual 6sp sedans. Truly a modern unicorn... (less than 450 sedans, about 675 ATS-V cars overall are 3 pedal monsters!)