would you rather have a 10.5 hotside and RNR's race intercooler (24x12x4) or revolver cams? Right now i'm at 310 on a mustang. Please do not suggest other mods.

 

I would go with coilovers, either ohlins or pss9

IMHO, handling is much important than hp

 

the 10.5 hotside is pretty cheap and can be installed by yourself with patience. You may see gains of like 7-10 whp over your current tune.
the rnr intercooler is a bit more expensive, will help ur car perform better, but you may not need it yet, as the stock intercooler is rather efficient for what u have.
Revolver cams have shown some good gains, but cams can be expensive to install, but you're probably looking at another 15-25 whp depending on the tune.
just offering my opinion, lets us know what u decide!

 

of the three, I vote for fmic, cams, and then hotside, in that order.

 

my hotside