will a front mount intercooler increase the performance of my 94 wrx with bailey dump valve?

 

Have a look in general, guy, there's a whole 3 page thread about intercoolers

 

And while you're at it, use search to look up the lack of benefit of a non-OEM dump valve

 

It will depend on what power level you are at for a start.
What power do you think you have?
What turbo are you running?
Is the dump valve the only mod?

 

remapped z4 ,ecu ss hks exhaust ,hks air filter ,walbro fuel pump that bout it not sure what its running at but is boosting up to 18 psi 20 on the motorway standard dump valve still as wen i put the bailey dumpvalve on before it slowed the car down

 

On a 94 WRX with the slanted intercooler you are already experiencing high air charge temperatures by 260 bhp and from a particular STi we did that was already over 280 bhp I know that there is power to pick up, typically 20 bhp over the slanted intercooler but you should not fit an FMIC unless you can remap the car.
My opinion is that a dump valve will do absolutely nothing for your performance, unless of course there is an existing problem with the O/E item that already performs well. It sounds like you found out that the Bailey DV would reduce performance anyway which is very often the case with aftermarket dump valves.
Save your money on the DV and put it towards a Simtek or secondhand Apexi Power F.C. You will not regret it and never look back from there.