Gtx 155 impeller and exhaust

[ClarksOffroad]

I have a 2002 gtx 155 that has a trashed impeller.
I need some recommendations to keep stock performance possibly more without dropping the rpm’s.
Also I am building my own free flow exhaust and was wondering if anyone else had already done it.

 

[CommonCold]

Shop manual says stock 4 tec impeller is 13-23°