It depends on your dump pipe design and air temps.

The spikes I was experiencing were only on cold nights.
Never hit boost cut, so weren't too serious. It effected smooth power delivery the most, which is a huge way towards good drivability.
I had owned my car for 3 months before i noticed it. Now being in the middle of summer your unlikely to experience them anyway.

Mine, although i think im going to replace the AFM VERY soon, gets spikes in the cold. However, i think i was getting this before my exhaust went on. Trying to remember back but my car at about 5 thou feels like it has a boost spike. Again, not sure if this is my AFM but im pretty sure it didnt do it before the TBE. Classic ECU's are alot more tollerant then the newer ECU's from what i have discovered with basic mods.

i've never hit a boost cut yet with no ecu and bigger intercooler and turbo.

and intake.

are you putting a cannon or a muffler

isn't a cannon a type of muffler?

I believe so :P. I think he means cannon or Oval shapped muffler (if theres a technical name for them)

Yeah what ever i meant just the straight 3/4" pipe

which bit is that?

the muffler

a 3/4 inch muffler?