Straight pipe backpressure problems?

Hi everyone, I'm new to the forum but hoping someone might be able to help.
I have a 1996 ZX6R which I use for track riding (not racing). My main goal is to indulge this hobby without spending large amounts of cash, track pace is secondary.
I had an off while riding the Phillip Island Grand Prix circuit (Turn 10 for those that know the track) and did some damage to the right hand side.
I easily (and cheaply) sourced (from wreckers mostly) the replacement parts I required (bar, lever, peg, brake pedal) however I also smashed up the silencer and have been unable to find a replacement.
I fabricated a replacement myself out of straight pipe and was hoping someone might be able to tell me what effect this might have on the bike. I'm not so much concerned about a potential drop in power (track pace is secondary) but being a self taught "mechanic" I'm concerned about potential damage that may be caused by not having the correct exhaust system and any backpressure issues that might arise.
Alternatively, does anyone know where I might find a replacement silencer to suit?
I have attached a photo to show where the custom pipe starts and length etc.
Thank you in advance to anyone who takes the time to offer advice.
I have a 1996 ZX6R which I use for track riding (not racing). My main goal is to indulge this hobby without spending large amounts of cash, track pace is secondary.
I had an off while riding the Phillip Island Grand Prix circuit (Turn 10 for those that know the track) and did some damage to the right hand side.
I easily (and cheaply) sourced (from wreckers mostly) the replacement parts I required (bar, lever, peg, brake pedal) however I also smashed up the silencer and have been unable to find a replacement.
I fabricated a replacement myself out of straight pipe and was hoping someone might be able to tell me what effect this might have on the bike. I'm not so much concerned about a potential drop in power (track pace is secondary) but being a self taught "mechanic" I'm concerned about potential damage that may be caused by not having the correct exhaust system and any backpressure issues that might arise.
Alternatively, does anyone know where I might find a replacement silencer to suit?
I have attached a photo to show where the custom pipe starts and length etc.
Thank you in advance to anyone who takes the time to offer advice.