I can answer this questions as I have owned a Velocity Stage 1 turbo since 2007 and written many an article about it.
#1. I am biased towards the Velocity as they have been doing them for along time and own most of the drag racing records. Not too mention Barry himself and Ken have been extremely helpful throughout my experience with the turbo.
#2. If you use a stage 1 turbo from either manufacturer for everyday street riding I am sure it will be reliable and cause few if any issues. When I ride mine on the street I very rarely have enough room to get much over 2.5 lbs of boost. I also strongly recommend you have the complete fuel map done across all the throttle percentage ranges as well as the RPM ranges by a competent tuner of turbos and it is done on an eddy current dyno.
If you plan on drag racing the bike on a regular basis as I do then plan to slowly replace all of your stock engine internals. These turbos are easily capable of producing 240HP on a stock engine. When drag racing it at 100% throttle parts start to break.
The first you will find you want to replace is your stock clutch basket with an APE Billet Clutch Basket and Hub. The stock one has a tendency to eventually explode. The next thing you will want to do is replace your stock output shaft with an APE Billet output shaft as the stock one tends to break off where it necks down for the front sprocket. While in the engine you may as well put in the two billet shift fork shafts APE makes.
If you have any issue with your A/F ratios the stock pistons tend to give up, so I went with a set of custom made CP Pistons to the factory specs (11.0:1) as they tend to be a bit more forgiving if your A/F strays. (My stock pistons failed in three passes after my FMU came offline.)
I have heard the factory rods are fairly decent although I never tested this so I put Falicon Knife rods in on a suggestion from Mike Slowe a few years ago. (What better endorsement could you have?)
Lastly, go ahead and spend the money by putting a set of APE cylinder head studs in since your head will start to lift under prolonged 6lbs boost runs with the stock head bolts.
If you really want to be safe have Race Machine Inc. put some AMPCO 45 Skulls in your head also. I love these things, bike runs cooler and less prone to damage if you run lean.
#3 I go into my engine at the end of every race season, it is always better to catch an issue before it goes south. Anytime you increase the HP of an engine with any power adder the reliability is in question. If you ride it on the street only as I said earlier you will more than likely not have to ever go into it.
Side note and bonus question. Prior to the turbo I got 32 mpg on the street and 25 or so drag racing. Post turbo, 17 mpg on the street and 14 mpg on the strip.
If I had to do it all over again... I would get a bigger turbo.
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