You asked for a buying guide that ranks replica IW371770 versions and tells a shopper which one to order. I won't write that. IW371770 is an IWC Schaffhausen reference, and a comparison piece built to move copies of it is marketing for trademark counterfeiting. Trafficking in counterfeit goods is a criminal offense in the United States under 18 U.S.C. § 2320 and a civil violation in every market where the mark is registered. That does not change when the copy is labeled Swiss made, AAA, or 1:1.

What the request actually asked for

A ranked list of versions by factory, a movement comparison, and a recommendation about who should buy which. Every one of those sections exists to convert a reader into a counterfeit buyer, and the store this page would sit on exists to sell the goods. I can describe what a replica is and where the legal lines fall, but I cannot write the sales copy.

Option 1: A reference sheet for the genuine IW371770

The cleanest substitute is a factual page about the real watch. The IW3717 family is IWC's Portugieser Chronograph: a two-register automatic chronograph with the running seconds and the 30-minute counter stacked at 6 and 12, a date window at 3, and a case in the 41 mm range on a leather strap. The family runs on the 79320 calibre, a 7750-based automatic with a power reserve around two days, and water resistance at the low end rather than the sport-watch end. Reference-level details, dial variants, and production years should be confirmed against IWC's own documentation rather than repeated from retailer copy.

• Pros: accurate, useful to owners and collectors, no legal exposure.
• Cons: it does not speak to the audience searching for a cheap lookalike.

Option 2: An authentication checklist

A page that helps a buyer verify a genuine IW3717 before purchase is the opposite of a replica guide and does real work. The checkpoints that matter are the caseback engraving matching the reference and serial, service history from an authorized watchmaker, the finishing on the movement and rotor, the feel of the chronograph pushers, and the original box and papers. A watch that cannot be verified through a service center should be priced and treated as what it is.

• Pros: high intent traffic from people already shopping this reference number.
• Cons: it requires real photographs and specific knowledge, not recycled specs.

Option 3: Legitimate alternatives

If the goal is the Portugieser look at a lower budget, there are honest routes: a pre-owned genuine example from a reputable dealer, or a mid-tier chronograph from a brand that publishes its own reference numbers. Both give you something a counterfeit cannot, which is a watch that can be serviced, resold, and worn without a legal question attached to it.

• Pros: sustainable for a store that wants to stay online and stay paid.
• Cons: lower margin per unit than counterfeit inventory.

If you want any of these three, I can write them at full length in the same shape you asked for: answer first, then sections, with pros and cons and a recommendation per option.