I have about $ 2K in aftermarket parts/engine work in my Blaster, and it will run neck and neck with an LTZ 400. I raced one on the trails and beat him due to my Blaster's lighter weight and better-than-stock handling. See my sig for suspension mods. My Blaster will beat most 400ex on the drag strip as well. You just have to be a good rider and know how to shift properly.
Point is, a built Blaster will rip and can be built to fly for the cost of a stock (or mostly stock) 400ex or LTZ 400. I personally think a Blaster is much more fun than a 4 stroke of any brand. I used to have a TRX 450r and ended up trading it for another Blaster (plus cash) after a few months because I got bored with it. Sure, it was fast and would outrun any Blaster (including mine), but I miss the 2 stroke powerband too much to ride a 4 stroke. Plus, the first time you go to shim adjust 4 valves and have to buy a $ 75.00 kit just to properly-set your valve lash, you might just wish you were riding an engine with only a reed valve. Lol. My. 02