Is this a successful way to go ? , or is the real GT30 turbine housing very different inside ? I have been offered a CHRA nearly identical to the HKS3037 except that the compressor wheel is about 1 mm larger at the inducer . For a two litre engine is there any advantage using a 50AR TO4E comp cover over the more normal HKS 60AR TO4E cover . My supplier in Australia has the HKS 73AR Turbine housing and judging by posts here this gives the best balence of response and power . So , how does one build a GT30 series with real good response and avoid the HKS premium price ???