I've spent a lot of time reading around the forums. Listening to tuners like Bill and Niki and the TIP is such an important part of your setup. Like has been said there's not much difference between the SFS, B5 V2.2 and V3. However most of the true 300 and beyond K04 and hybrids cars use the V2/2.2. Again the V2.2 is what Bill and Niki recommend and that justifies the extra cost to me.
On the K03 platform cars both Bill and Niki recommend either the SCS or forget TIPs as the CM is more restrictive. Niki posted on FB at the turn of the year that on a car he tuned he swaped from a CM to a Forge TIP and got big gains from the increased flow of the forge TIP. Here's a photo of the Forge and CM side by side that Niki posted at the time. You can see how much the CM TIP tapers away compared to the forge one.

With TIPs like many things you get what you pay for...