What are the results of removing the SLP Loudmouth dual-dual exhaust and running the pipes straight back from the cats with no mufflers?

Noise-factor (more trebble-y?) HP gains (OR possible losses)?

She's a 1999 Firehawk M6 with the standard camshaft and some modifications:
NGK Iridiums & Magnecore wires
Holley PowerShot airfilter
Ram Air (true) with baffles removed
SLP LM dd
Hypertech PPIII 160degree set, Non-RFG, Powertuned
160degree stat