I'm going to buy a 2005 Mach Z with some mods done to it. I need to know what WORKS & WHAT DOESN'T. The sled I'm considering has Crank Shop Twin Pipes, TFI Box, V-Force Reeds, Advanced Timing (not sure how much), Chuckaroo Porting & Chuckaroo Clutching. Any idea about how much all these mods cost? Are they worth it & do they WORK well without creating reliability concerns?!? The seller claims the sled is trailable... what do you guys think? I'm paying around $6000 IF I buy it. HELP!