What else is broken and/or demaged in the engine? Thats not the first case of bearings failure on TB, which I heard unfortunately. With what oil did you drive, at what level (just for my information)? Bearings worn with using of the car and have to be replaced on performance car with high mileage. At what price did you order Q2 diff? Quaife is at better price now. Very good upgrade for powerful FWD car. What clutch did you order. Probably something upgraded, stage 1 for example (upgraded pressure plate)? I make a little research and found flow capacity of 224 cc/min for GTA injectors, not so bigger compared to 189 cc/min stock yellow one. Did you have some problem with stock one or that have been good deal? I don't think that installing of GT2860RS or GT2554R will be much different in time, work and parts which have to be done. The question is what you want from the car and for what you have been prepared (money) and of course the right guy/guys which will make the project. What you plan to change in your engine? First rebuild your engine and then think for upgrades. The thing that I have in mind regarding downpipe was to give my car to my friend which make exhaust manifold and all other components of exhaust system, turbo piping, strut braces (weld stainless steel, aluminium, titanium). He to make downpipe and to send it to you, for some price and delivery tax of course.