I wouldn't expect them to honour it bill after 50+ thousand miles, and having killed 5 turbos attached to that mani. If your tubular hasn't either cracked or warped a flange in 50K miles, I'll be stunned.
If the new one lasts as long it's no biggy.
The hastle of new downpipe, lines etc, new exhaust housing for turbo etc was too much for me to stomach after the full engine rebuild, so I replaced it with the same.
Fitting was no big deal. (stealth did it)
Also I know what I have works, and is faily reliable. More power is unnecessary, so running it lower boost, and safe is the way forward.
450+ in the polo must be a major joke. I know it's hardly useable in mine which is heavier, has wider tyres/track etc.
Good to say you can though.