First of all, this is not serious but this is how I and others have dealt with on3 turbo kit v band leaks and it seems to be the best way to go about it.
The biggest issue I found with my v bands is that the clamping area is actually too damn large besides the clamps are just low quality.
Fix: Buy 2.5 inch V band clamps from V-Band assemblies, V-Band Clamp, RPS-V-clamp | RacePartSolutions.com
Total cost with coupon code 0001 (10% off) and shipping= Under $60.00
Wonder which one is which
Take notice of the clamping zone, the RPS ones are much smaller and actually clamp the connections tight like they should be.
Great, now that you have better v band clamps you may even be able to get away with some rtv copper silicone but unfortunately you may need gaskets like I did.
There are many types of gaskets but due to the extreme temps and pressure you really need something that will hold.
Modularspeed told me that these gaskets have held for him so that is what I went with.
OBX Gasket Downpipe 3 Bolt 2.5" w/ Metal Ring | eBay
I bought them and cut the tabs off to get this.
I also located a cheaper source...so instead of 16 on ebay they are 9 here:
OBX Gasket Downpipe 3 Bolt 2.5'' w/ Metal Ring - Part Number: N/A - Sparktec Motorsports
I ordered them and got them from cali to Delaware in 5 days.
I installed them with the new clamps, dry, and have no leaking issues as far as I can tell. Time will tell how they hold up.
If you do all this and still have issues you could pick up some of this stuff.
Some people have actually used just this stuff with no gaskets but it didnt seem like a very good solution to me.
Anyways, hopefully his can help some on3 guys with leaks since it seems to be a universal problem for us.