I enquired about fitting the Forge alongside the THS and I understand there is a couple of issues:
1: You would need to have custom Forge Silicon Pipes made as the THS comes with its own 'custom' pipes to replace the OEM pipes.
All Forge hoses are 'custom' made! All you would need to know is the diameter of the connections on the THS (and the type of connection too), let Forge know, and they'll be able to make the hoses for you. Forge hoses are never an 'exact' fit - they usually require trimming to get a successful fit - a bit fiddly - but perfectly OK when done.
2: I was led to believe that 'lag' may be an issue due to the massive(!) increase in IC size what with the larger THS and Forge.
I personally don't have any lag with my Forge and S3 cooler on a K03.
It is really all relative, and a bit of a compromise. If you genuinely get plagued by heatsoak and power drop off, then a touch more lag might be worth it (and I'm sure REVO and the likes could map out the lag). But if you never actually get heatsoak on just the standard plastic GTI cooler - and just wanna upgrade for sheer vanity, then the lag will probably p!ss you off. You really and honestly need to carefully assess what heatsoak you currently get, and then what the ultimate goal of swapping the i/cs will achieve.
3: Again I could be talking BS?
Why break the habit of a lifetime . . . .
Sorry, mate, couldn't resist!
Am I wrong about the Lag issue TT?
Are you K03 or K04? That might have a difference!