the x37 is wonderful for the money it's the best option out there imo. I was able to land an x37 with a ported stock manifold, big inlet, turbosmart wga with 14 psi spring with just 10k on the setup for 1g shipped. Little while later I seen an x47 setup for like 1400 shipped but it did not come with a ported manifold I'm not even sure if it came with the WGA so all told the x37 is still the better deal if and when you can find a used one as they don't sell them new anymore. If you just want good reliable power on stock fuel system and stock engine with a fat powerband and not alot of change in spool characteristics it's the best setup because I feel the x47 flows enough when on e30 to get outside the efficiency range of the stock fuel system. The x37 you can push it to 100% of it's capabilities without taxing the fuel system...the x47 is on the borderline of weather or not that's the case. mean the x47r and some of the others may be better if you want to upgrade your fuel system I did not so x37 makes more sense to me. This thing moves as it is with just 270 whp on 93. I pulled on a modded 350z ( not sure on exact mods but exhaust for sure) when I was on my 1st revision only doing like 225 whp so if I raced the same car again I'd destroy it. I understand the need for more power for some but really what the x37 does is really enough for most on this small front drive hatch. It def puts the car in a completely different performance area as far as cars you can compete with and cars you can beat compared to a fbo stock turbo setup. When you take a second off your quarter mile time and gain over 10 mph that is a pretty significant difference I don't think some on here realize just how much that is. They see peak to peak numbers and torque don't change much so they think "Is it really worth it?" I'm telling you man...forget peak to peak numbers...the area across the curve is EXTREMELY SIGNIFICANT...trust me when I say that. It isn't even remotely close between a proper x37 setup and stock turbo setup...it just isn't I don't care what torque someone did on the stock turbo. They only do that for a super short timeframe low down...the x37 does similar torque numbers peak but holds that number out much much longer and the power is significantly higher and it stays there across the whole powerband well past where the stock turbo dies off and well past 6k to 7k. It puts you into an entirely different performance bracket. All that for a g is unreal performance for the dollar. You'd be happy with any of them I think but if you can find a good used x37 it's still the best bang for the buck in my opinion.
