Originally Posted by stevieturbo

A friend has a GT4094 sitting and un-used. In Comparison to the Precision unit, the Garret's turbine looks huge and bulky and carrying a lot of weight.
I think the modern Garrett billet units also have improved turbine wheels compared to the old stuff, although the only ones Ive seen so far are smaller direct replacement type units, so cant compare to the generic stuff.

So not honestly sure switching to another old design Garrett would be the best option.

The Precision unit could be bought for less than £1500 new. Not sure how that would compare to a new billet Garrett of similar performance. They also do Garrett replacements that should be almost a drop in unit

If the rest of your car will support 2 bar, then go for it. It still wont address boost lag between gears though.
Cheapest and easiest thing is to ensure boost control is optimised as much as possible first.