doesnt look to be an incredibly well designed kit. and id be willing to bet that "easy 410" whp requires using way more boost than your car will really be able to take for more than a day. There are a lot of kits comming out for 3800s now and a lot of them, this one included, seem to be too focused on power and not focused enough on good design and practicality. in other words, they will make you go fast for a year, and then your car will break down because the kit doesnt run SAFELY on the car. I would recomend the Cartuning Performance 3800 turbo kit. It is very well designed. For 3000 dollars it will put down 296 whp, but with the intercooler (coming out soon, ~6/700 bucks) you can run additional boost and timing safely and be able to put out around 400 whp, but you may need to go for the 300 dollar turbo upgrade to get that much power.
http://www.3800performance.com/Merch...ry_Code=EC#GTP