My thoughts as well, but wait, that's one of many things Ive done over the years! Hell I built the whole exhaust system on the TVR from scratch for a fraction of that, unfortunately NZ does not seem to have people that are that spendy spendy...Dang, I need to get into the header-making business.
Ron are your SBF bundle of snakes still available..? If so Please call or text me at 305-986-2968. Thank youI will have a set available for a SBF that are provided with a Superformance roller. My engine has the Gurney Heads so they don't work. PM me if interested.
Well... If you have a leak the backpressure in the exhaustsystem will cause gasses to leak out, not air to enter the system. Unless you have some sort of a ejector causing negative pressure in the exhaust. So it won't make that big difference.Adding my .02 cents here.....for you EFI guys, that exhaust needs to be air-tight, i.e. no leaks, no dependency on Hi-Temp silicone, etc. Any undesired oxygen (leak) will get picked up by the very sensitive wide-band O2 sensor and play havoc with your target Air-Fuel ratio, which can result in the car running pig rich. So a good quality stainless exhaust with DOUBLE-SLIP joints at the primary-collector union, and preferably V-band clamps at the Collector-Muffler union will work extremely well.
Now, the more advanced ECU/FADECs can be set to open loop in some or all rpm/load scenarios by a competent tuner, however, that is not the intent of EFI, so remember....Shit in-Shit out!