i had the same issues w/ the spec and fought it for 5 gals and now i have the rex & top p5's love them a LOT. i just sold my RB MODS S7 cause i just run the p5's now. you couldnt ask for a better mill and easy as heck to break it in. right out of the box both of mine fired right up and ran ran ran. 5gals on the top and 2 on the rex. here is the best setup for them ive found. mugen black fiber shoes,1.0 springs,and the 053 pipe -JP1 header combo. it will rip butt.