Turbo value question
 

Hi guys ( and gals ), just looking for some advice on the value of my turbo. I'm currently using a VF28 on my car but want to upgrade to a TD05 20G. I have no idea what my 28 is worth, it's a really nice fast spooling turbo. No smoke and holds boost perfectly. According to my mapper the car is running around the 340 / 350 mark at the mo.
Any advice would be very much appreciated.
Thanks people.

Anybody ???