1991rx7vert

well I decided to continue on with my build...this damn recession has been kicking my ****...I have a limited budget to finish my build now (I would like to drive it by the end of the summer!!!)...my question is can I tune my 1991 rx7 vert myself, this is my setup I have 13b-re stock twins with a haltech e6x and a inovative wideband controller...does anyone know if there is a map for a stock 13b-re around...if so can I just download it and start it up and run it for now without doing any harm to the engine??? I still have to buy the exhaust, fabricated down pipe, and a few odds and ends....the tuner wants about $650 to tune with the dino and another 150 to fabricate the down pipe...Can I just use the stock exhaust for now its in good condition??...and if anyone has any suggestions on how I can get it to run on grass clipping please feel free to let me know!!!! regular is $4.42 in ny ....heating oil up from $1000 a season to $5200 this season WTF how the hell am I supposed to keep warm this year...oh yeah I can always burn my furniture...I'm depressed again see you all in a couple of months again after I get tired of looking the car it in the garage and can't drive it....