I have a 87 mustang gt with several bolt on's including 93 cobra heads with 1.7 rr 65mm t/b headers with full 2.5 in exhaust. The car is still speed density with absolutely no idle problems .I'm wanting to add  either the patroit aluninum heads or maybe have the cobra heads cnc ported with 194/160 valve and either the steeda #19 cam with 115 lobe seperation or the comp xe270hr with 114 lobe seperation.From what i've read as long as you keep the l/s above 114 the speed density system will work .Has anyone triad either set up and how did it idle?What about power?I'd like to get around 300 on horsepower and torque.Idon't want to spend the extra money for mass air conversion if the speed density will work.  

i got a 1988 mustang gt speed density with trickflow twisted wedge heads. a comp cam xe270hr and 100 shot nos. no problems at all. another good speed density cam is the crower 15511