doesn't anyone know the limits of our 2.5" system horsepower wise. I have read through the forum and saw that on the stock set up and up to around 550 you can just gut the pre-cats and call it a day. reason I'm after this information is because i'm working a long term engine build and I find it hard to swallow ~1500 for downpipes. the rest of the exhaust is not a problem as i have a local shop near me that does GREAT work...just trying to see if the 2.5 inch system is good around the 650-700 hp ranges.

i'm in the beginning stages of my build and i'm not in a hurry so the more information i can gather upfront the better so when it comes time for exhaust i'll be prepared.

so far i have ported and polished the heads/intake manifold/exhaust manifold and i have a tial 770r kit waiting for install (down the road).

Also...

I'm coming from the 1.8t and 2.7t platforms so i'm not do familiar with lag and spool times for these turbos on the 4.2 engines. on the 2.7t they hit hard around 4k rmps or alittle harder and carry through to alittle over 7k typically. Just wondering if anyone knows these states based on our engines as it should be much better since we flow more air and have more displacement.

thanks!

oh and yes 1st post, just been waiting for a good time to starting chatting haha