Hello if recently brought a mk1 octavia vrs 1.8t, it's had stage1 map a few pipes, dumpvalve and power flow backbox, the map was done on a rolling road so it's set up for everything on it, so I brought the car and the rear mount had gone on the engine and this caused the flexy on the exhaust to split near the turbo so I went and had a 3inch straight pipe fitted and custom made as I was going to boost the car a little, since this exhaust has been fitted the car won't go over 4k when revving and when driving it will half boost to 4k then Lagg its way past it, it almost feels like I'm tapping the break as I'm driving, any ideas? Maybe new map to set up the new exhaust? I have no idea I'm lost