Hey guys I have an odd sort of question. I am rebuilding my 2002 wrx motor at the moment because at 130k miles the bolt holding my timing tensioner pulley snapped. Unfortunately my valves made enough contact with the pistons to require replacement. My car was previously tuned at p&l motorsports for a catless uppipe and downpipe. I called them and asked for their opinion and was told cp forged pistons would be best. My goals are to have it e85 capable in the coming year, a new header, possibly a vf39 and better tmic. I bought the cp pistons after being told I wouldn't need a retune by P&L. According to them my compression is only changing from 8.0:1 to 8.2:1. I trust their opinion but I always like to get more than one.
In your opinion do I need a retune? I'm also wondering is it absolutely necessary to let the car warm up at idle with forged pistons?
Im only asking because I honestly need some guidance and this is my first rebuild!