One example of a kit. You will need to install idler screws of you plan on keeping the stock carbs. http://www.ebay.com/itm/YAMAHA-350-BANSHEE-AFTERMARKET-THROTTLE-CABLE-CAPS-/130602594079?pt=Motors_ATV_Parts_Accessories&hash=item1e68856f1f&vxp=mtr
I had a sling shot in my DM, swapped it out for a Direct Drive lock, works better. I had 3 balls in the slingshot and 6 toomey springs. It did hold the clutch. The main reason I switched is easy clutch change out.
Stock is the best way to go if you are not a tuner. An adjustable timing plate will be the best bet for waht you are proposing. You can throw timing at any engine and make power for a while, it will not last though. You do not need a Dyna to build an awesome engine.
Be very careful with the curves, you can detonate an Alcohol motor quick. Curve three wiil give you about 6 degrees. I run one on mt DM but it is on stock curve. I like the digital spark duration. That little bastard can cost you a shitload of money if you advance too much. Most guys hate them but I have had decent luck with mine. I do carry two stock CDI's to the drags just in case.