looking to buy big mouth exhaust system for my 240z .i want full exhaust 2.5 or 3 inch.

anyone know which company have this exhaust to the 240z without any cuts or modified to install on my z?

Forget 3 inch.

Motorsport Auto offers several 2.5" pre-fab systems.

Why? I think the trend is silly. Put one on a Civic it makes it go faster!

2.5" should be plenty on a NA L24/L28. The car/exhaust you are using for an example looks to have a custom fabricated Stainless exhaust. The TIG weld is visible just under the car. Full stainless can be super clean but also cost prohibitive.

You can buy a muffler like that from a number of companies. You'll have to look around. First companies that come to mind... 5Zigen, Apexi, Magnaflow?, etc. They likely sell universal fit ones with the inlet and outlet you desire.

2.5 is plenty large. I have MSA's premium 2.5 exhaust with a midpipe muffler to tame it a bit. It's mellow, somewhat louder than I'd really like, and it almost has a tiny hint of ricer-car crackle to it. I sure as heck wouldn't want anything larger.

Remember that the original exhaust was just under 2". If you go too small, you get back pressure. If you go too large, you get too low exhaust velocity and don't benefit from exhaust scavanging. There's a "just right" middle zone that's probably right around 2". But try to find a 2" aftermarket exhaust!

i dont think anyone makes a bolt on cat back like your looking for....but hks , greedy and blitz are the best sound i have found for l motors..and they all make 2.5 and 3{i ould go 2.5} uni's

for proper fitment look at the old school japanese companies. Kameari, kakimoto, and Rs Start all have the big exhaust without modification and will be "bolt on" depending on your header.

I agree with posts above. 2-1/2" is more than adequate.

I'm an older guy. I know it's a "style" thing, but to my eye, a megaphone exhaust on a classic Z looks high-schoolish / "ricer-boy" silly...

Rest of the car in the pic looks pretty nice though.