1) Is the 4" tip exhaust available for s13? - yes in stock
2) Is it 4" all the way back or just the actual tips itself? - It is 3" to dual 4" tips
3) Will the testpipe bolt onto a stock s13 header? - Yes
4) My car is lowered on tein coilovers how low does the exhaust hang? (roads are bumpy here)
This is one on my S13 KAT
thanks
Ken