the only real problem with a vj14 hotside (p-12) is that the flow out is restrictive...
a vj11 is bigger and will spool a bit slower but running a t-bird compressor id run at least a p-20 hotside..
to disperse all the exhaust that the t bird compressor is pushing in... its a game of give and take... thare are ways to reduce boost lag later after its up and running correctly...
you can see the size of the exhaust hole after the turbine wheel in this pic... the idea is to match the flow you will need with the spool you want... another thing to remember is the size of the W/G hole... its so tiny on the vj-14 that at higher boost levels, the compressor will create more airflow than the W/G can get rid of... this causes severe boost creep at the top end...the tiny hole can only bypass so much air before it can flow no more.. and the remaining air must pass over the turbine wheel, and spools the turbo past the set boost pressure (creep, spike)....
shrinking up the hard pipes from say a 2.5 to a 2in from the turbo to the intercooler will spool up about 500rpm faster...the less area the turbo must fill with air, before creating usable boost
thus reducing lag...
running a recircing BOV will drop the lag very signifigantly between shifts... almost like thare is no lag at all between shifts...
this effect is exaggerated the bigger the turbo you run...
also, 12*, the sweet spot in our timing is 12*...
13* and you will lose up top.. 10* and you lose spool and torque... 12 is the best timing for any B6t with whatever turbo your running...
ive tried everything from 8* to 15* thares just something about 12* that it likes... i think the dist. is setup for 12* and anything else and your messing with its perameters...